Exotic Driving Experience
Jan 16

How To Build a 12 Second Mustang 5.0 Fox-body

Posted in On Race Track info


To build a 12 second Mustang 5.0 Fox-body is not too difficult a task, as stock these cars are full of drag racing potential.
There have probably been more than a few articles written about making your 5.0 run 12′s, this is my take on the whole subject.

While the new 2011 “Coyote” 5.0 engine in Ford’s latest Mustang creation can run that fast with just some good driving and tires, our Fox-body going to need a little help to break 100 mph in the quartermile. By imitating NHRA “Stock” type of combination, you’ll be able to reach the 12′s without major engine work.

NHRA “Stock Eliminator” cars follow a strict set of rules that us hobby racers are not bound by. But utilizing some of the techniques the pros use, we can make your Fox-Body Mustang fly. By maximizing traction and minimizing 60′ times, you can run in the 12′s without a lot of power.

To get the best traction we need racing tires, for a street/strip car you need drag radials. For a strip only car slicks will most likely be quicker. 275/60 x 15 drag radials or 28 x 9 x15 slicks will give you the traction you need to rip off some 1.60′s in the 60′ times. Mount your tires on a 15 x 8 aluminum racing wheel with a 5 or 5.5″ backspacing. Don’t forget the longer 3″ wheel studs to hold them on securely.

To take advantage of that big tall tire out back you’ll need a serious drag racing gear ratio. Forget about the 3.55 or 3.73′s, we want to go racing, the heck with the gas mileage. Besides that’s what overdrive is for anyway. To be able to hit the 12′s you need a 4.30 gear, or at a minimum 4.10′s.

Refill your differential with some synthetic gear oil and you should be good to go. If your cars a high miler (most Fox’s are), seriously consider rebuilding or replacing your posi-traction unit while everythings apart. Don’t waste your money on an expensive rear-end support (cover), totally unnecessary until you’re going a lot faster. My 1993 Mustang has gone as quick/fast as 9.12 @ 152.44 without one, so trust me on this point.

If your 5.0 Mustang has a T-5 5 speed transmission do yourself a favor and buy a good high performance clutch and pressure plate for your car. Replacing the flywheel with a steel one is always a good idea on any car that’s going to be raced. They’re very inexpensive compared to the cost of repairing the damage caused by your over 100K miles heat-cracked stock flywheel!

If you’re rocking an AOD in your car, it’s going to require a bit more work ($$$) to make it live for very long in the racing environment. Ideally you should install a high performance rebuild kit in it, with a shift kit to firm up your shifts and quicken them as well. High stall torque convertor is absolutely essential to get off the starting line as quick as possible.

Recommending the proper one for your particular car is a whole story in itself. Call a reputable convertor manufacturer and spend some time on the phone with them. That way they can match your convertor stall speed to your combination and driving needs. Match it up with a B&M ratchet shifter so you’ll be able to hit all those gears and stay locked out of reverse!

Next time we’ll cover more info to get you closer to running 12 second ET’s in your 5.0 Mustang . If there’s anything you have questions about ask away in the comments section below.

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136 Responses to “How To Build a 12 Second Mustang 5.0 Fox-body”

  1. Rich T says:

    Tommy This is a first for me so I hope to get a response,

    I have a 1990 coupe LX 5.0 with 240,000 all by me as I am the original owner of the car. The following Mods have been done to my car 1.5/8 equal length shorty header’s and 2.5 pipes with flow masters to the rear. 65 MM throttle body and cold air intake, The original auto trans has a TCI shift kit with a 2400 stall converter with a trans cooler 4.10 gears in the rear , also have under drive pulleys with 235/60/15 mickey Thomson et radials on old state trooper steal rims, and lake wood drag shocks up front .
    I would like to know if I am heading in the right direction and my next buy would be upper and lower intake I try to do all the work myself if I can as its much more satisfying in the long run. Looking to hear back from you and what’s your best guess on what she will run this spring as I just put the converter in and it’s raining now till May , so plenty of time to work on her.

    • Tommy says:

      Rich,
      It’s good to hear you’re trying to do your own work. That is definitely the way to go. That way if/when you break it, you’ll be able to fix it. All the money you save on labor costs can go towards more parts!!!
      With 240K miles on your car it will be hard to estimate ETS. My guess would be solidly in the 13′s for now. When budget permits a rebuild with a boost in compression, a set of aluminum heads and a hotter cam and you’ll be heading for the 11′s depending on parts choices of course. Check out my articles for a few rear suspension upgrades you’ll probably need to make as well. Good luck and keep me posted.
      Tommy

  2. Ken says:

    Hi Tommy,
    It seems that this question will never “get old”. Is there a reliable way to add nitrous to my 90 stang with forged internals and about 10k miles on the rebuild? I want to be in the mid to low 12s.. I have some things done to motor/driveline/suspension but i just dont have the funds to buy that dart block and afr head.. etc.. I have 306 with x 302 heads, e 303 cam, cobra upper/lower, 70mm TB, 73 mm calibrated for my 30lbs injectors, fender CAI,1.7 RR, 3.55 gears, alumn driveshaft, 17inch cobra wheels and brakes, 5 speed tremec t5 hd z spec 2 stage clutch, i still have the stock rad and clutch fan, I want to go fast.. Plz Help…

    thanks for your time
    Ken

    • Tommy says:

      Ken,
      With the engine you have built I see no reason why you shouldn’t be able to achieve your goals. Nitrous Express makes a decent kit that will fit your car, part #20101-05 available at Jegs and elsewhere. It’s an adjustable plate system that can give you anywhere from 50-300 HP as a single stage and twice that if you upgrade to a two stage. YIKES!
      Now I’m NOT suggesting you add a 300 shot to your car but a nice 100, 125 or even a 150 shot could be made to work here. Along with the kit you’ll need to add a 255LPH fuel pump and adjustable pressure regulator, if you don’t already have them. A quick trip to the chassis dyno shop for a tune would also save a lot of unnecessary grief and allow you to optimize fuel pressure and ignition timing for maximum power and engine longevity. Add a set of drag radials and you’ll be right in the ballpark as far as your ET goals are concerned. Getting rid of the heavy clutch fan is not a bad idea and will save a few HP for you. The stock radiator can probably stay a while longer, unless cooling becomes a problem for you.
      Tommy

  3. Mike says:

    Hey tommy,
    I have a 92 mustang with mt et streets in 275/50/15.just installed an edelbrock performer rpm upper and lower intake and gained 3/10ths in the quarter mile. Best car has run is 14.17. Car has aod tranny with stock converter with shift kit and BM Ratchet shifter. Rear is 4.10 and I also have bbk CAI with 24lb injectors and a 255 Lph pump and a 70mm throttle body. What should I do in order to lower my et. Replacing the stock heads would be my first guess. I could just give it a 100 shot and see where that gets me. Car has 160000 miles on it. My 16 yr old son races it in the high school challenge and I would like it to run a little faster. For him I would like a 12.5 car I think that he would have even more fun with a faster car. Thanks for any info u could provide

    • Tommy says:

      Mike,
      The 100 shot would definitely cut a second or so off your ET. HOWEVER, I’m not sure that’s such a great idea on a 160,000 mile shortblock.
      My first recommendation for your combo would be to get rid of the stock torque convertor for something with quite a bit more stall speed (around 3,000rpm).
      Check with a few trans part manufacturers for what they have in stock. While it’s a pain in the butt to install, it’s (much) cheaper than a pair of heads and at this point in your project will bring big returns.
      You’ll need one eventually anyway, as the launch is all important in a 1/4 mile drag car. Be sure to add a trans cooler when you install it and change your trans fluid to a full synthetic fluid as well.
      These will maximize performance and trans life for you.
      Then you can have your son practice burnouts and launching the car to get the most bang for your buck.
      Wheel hop may become an issue at the higher launch rpm, so see my article on suspension mods to stop it.
      Lower control arms should be the first item you buy on the list of mods.
      In order to go fast you need to get ALL the power you have now to the ground before you add more.
      Good luck and race safe. Keep me posted on your progress.
      Tommy

  4. Keith says:

    Hey Tommy, I have an 87 Mustang GT, with a rebuilt ford racing crate engine. It is a 306 with all forged bottom end, has a b303 cam with 1.72 roller rockers, ported gt40x heads, port matched cobra upper and lower intake, with phenolic spacer between upper and lower intake. 70mm throttle body with 73mm MAF. Shorty headers, with offroad h-pipe and flowmaster catback. Got a dyno tune last fall and it dynoed 289 rwhp and 321 rwtq. It has a 95 mustang gt rear axle, tubular rear upper and lower control arms, air ride shocks. It also has an tremec 3550 trans with an aluminum driveshaft and 3.73 rear gearing, not sure on the clutch but it feels really nice and grabby. I’ve never had it to the track, do you have any ideas on the ballpark you think I should be in? Ive been debating on drag radials, because i daily drive it, not very far though. Nitto 555r or nt05r? or maybe mickey thompson et streets?

    • Tommy says:

      Keith,
      Sorry it took so long to reply to you, went to Cocoa Beach for a little R&R with the wife.
      Anyhow, on to your question. I think that you car should be able to run in the 12′s with an aggressive driving style and some testing and tuning.
      For tires I would pick something around 26″ tall considering your choice of gearing (3.73). This will get your rpms into the powerband of your combo nicely.
      If you do any street driving at all and these are going to be your daily driving tires, definitely go with the DR’S.
      ET Streets are cool, but NOT in the rain, (very dangerous). Now if you live in the desert SW where it never rains….
      Something in a 255 to 275 width should suit you well.
      I hope this helps, keep in touch.
      Tommy

  5. Bobby says:

    Tommy, I really appreciate the speedy response. When I was putting this combo together I pretty much knew the 2.02 High Ports were a bit big but figured with the NOS it would be ok, plus I wanted to leave myself room to grow. (I have plans to build a stroked out 351 and put it in a coupe using these heads.) I’m building the convertible as a street car with only a few visits to the track. (I just dont like the look of a roll bar with the top down) I have a set of the old steel Will Burt High Ports with 1.94 and 1.62 valves that are O-ringed with a mild port and polish job. In your opinion should I swap them out onto my 306ci for better performance or would it not make that much of a difference? Thanks again for your help!

    • Tommy says:

      Now you’re talking. A 408CID windsor with a decent shot in a flyweight coupe is 9 second territory my friend. I’m not real familiar with the Will Burt heads myself. I would say if the intake port volume (CC’s) is smaller than the High Ports, then they’d be a good fit on your 306. Intake port volume actually has more impact on air flow velocity (low speed torque) than valve size. If the port volumes are similar, then I would’nt bother changing them out. The other alternative would be to go with a tight 4.30 gear and spin the hell out of the small motor. But I’m not sure what sort of bottom end, crank and rods you’re running. Don’t want to put a window in the oilpan you know (that blows).

  6. Bobby says:

    I’m trying to figure out what kind of horse power and torque my combination is making and also what it should run in a quarter mile. I have a 1989 LX Convertible 5.0. it is a stock block with srew in freeze plugs and a main girdle with all ARP bolts inside and out. The bottom end is all balanced, it has dome pistons (part#7061P) .30 over bore,the cam is a crower cam (part#513) 288/298-228/234–512/531. box stock Trick Flow High Ports 2.02int 1.60exh valves, 1.6 crane roller rockers, Trick Flow street heat intake. 75mm professional products throttle boby and 75mm egr delete plate, 30lb fuel injectors, 76mm pro flow mass air meter, 1/2” spacer between the upper and lower intake, MAC 1 3/4” long tube headers with a BBK 2 1/2” X-PIPE, complete 2 1/2” Flowmaster exhaust all the way to the tail pipes, BBK adjustable fuel pressure regulator, 255lph walboro fuel pump, Taylor 409 10mm plug wires, MSD cap rotor and coil. Transmission is a PA Super Comp C-4 with trans brake with 3200 stahl converter. Rear is 8.8 with 3.73 gears. Suspension includes Lakewood 90/10′s on front, 50/50′s on rear, JEGS adjustable upper and lower rear control arms with solid bushings. I have solid motor mounts and solid trans mount. FRPP aluminum drive shaft with a lakewwood drive shaft loop. Aluminum AFCO radiator and electric fan. Rims are 15×3 1/2 front and 15×10 rear with MT 275/60/15 DRAG RADIALS. Power adder is 150-200 shot NOS. I know that I still have work to do (frame connectors, etc.) but I’m not quite finished with the car. But with what I have listed where do you think I should be as far as HP and 1/4 mile times? I’ve read your other post and you seem to have a pretty good knowledge about these Mustangs and would greatly appreciate a response. Thanks!!

    • Tommy says:

      Bobby,
      Keep in mind that all I can do is estimate power numbers. But looking at what you put together, it sounds to me like you have a good combo there. Starting at the beginning you have a 306 cu. in. high compression ( 9.5/10:1 ?) with some really nice heads and a healthy cam/intake setup. The heads (2.02 intake and 1 3/4 headers) are a bit large for your cubes NA, but will really come alive with the juice. Depending on your maximum rpm you SHOULD be making somewhere between 300-350hp NA with similar torque @ the flywheel. Lose around 20% to the wheels and I would estimate you are CAPABLE of high 11′s, low 12′s NA and take another half second off for the nitrous. Because your heads and headers are oversize, you may experience a loss of bottom end torque NA and ET’S will suffer. But throw a well tuned 100/125 shot on her and hold on tight. IF you have your suspension/chassis/driving technique optimized, you’ll be able to wring out all of the motors potential. As soon as the weather warms up in your area it’s time to hit the track for test and tune night. There you can experiment with tire pressures, fuel pressure, ignition timing, pinion angle, shift points, etc. Get yourself a log book and change one thing at a time, if you went faster, note the change and then try changing something else. If it went slower, change it back to the way it was. THIS is how the professionals get to run sick times in their cars. By optimizing EVERYTHING about your combo (driver too) you’ll be the first to cross the stripe more often than not. Don’t forget that you’ll need a rollbar in your convertible along with the proper safety harnesses/helmet, etc. It will definitely help to stiffen your car, which Mustang convertibles need badly. I’m not sure how much street/track time you plan on doing, but I would look for as many places as possible to lose weight. Convertibles already have a weight disadvantage going in and losing weight is as good as adding hp, for every 100 pounds lighter you are, the car will cut .12 seconds from your ET. Let me know how you make out and good luck.

  7. alex white says:

    Hey I talked to you before bout a 91 conv. I took apart the block its not a 331 its a 308 forged internals what all you think I need to run low 13 or 12 I got a tremec tko 3550 and 373 gear now took everything from conv. And pit it in a 87 mustang coupe thanks in advance

    • Tommy says:

      Alex,
      Putting all your parts in a coupe is definitely a step in the right direction. That convertible is probably 400 lbs. heavier, which cost you around 4-5 tenths in ET. The forged internals is going to come in handy for your project, as we can turn it tight and make it right. lol
      A set of aluminum heads with a 170cc intake port http://www.summitracing.com/parts/edl-60289/overview/make/ford and a small cam http://www.summitracing.com/parts/fms-m-6250-e303/overview/make/ford combined with an AGGRESSIVE driving style and GOOD tires will put you in the ball park. Add in some suspension improvements, so you can put your new found power to the pavement and you are there. http://www.bestracingtips.com/racing-tips/perfecting-the-mustang-5-0-launch-part-2/
      Be sure and follow Edelbrocks guidelines for proper head bolts and gaskets to go along with your new heads. 1 5/8″ headers are what you need for these heads on a 308 cube motor. These parts provide a good baseline for future improvements, (11′s) should your budget allow it in the future. I know the heads are expensive (still cheaper than a supercharger) but any SERIOUS build of the 5.0L Ford will work MUCH BETTER if you address it’s achilles heel (bad heads) in the beginning.

  8. Help please. :) . 89 hatch drag car 10 way adjustable front and rear, coil overs 175/150. 306 boss turbo c-4. Runs low 6,s in 8th. 26×9 MT best 60ft 1:47
    :( 117 in 8th. Car shocks the tires first then raises up. Set to 90/10 and 50/50 rear. Upr strings are only a few turns up front and rear. Leaves straight w the anti roll bar Wolfe upper and lowers all solid mounts. 2.5 pinon angle. Tire pressure 13
    Lbs. any help would be great!!! Thank you.

    • Tommy says:

      Anthony,
      Forgive me if I’m a little dense today, but I’m not really sure what your question/problem is that you are having? While I’m at it a little more info on your car would help me. What size/stall convertor, rearend gear, tire pressure, rpm at finish line?
      If you’re having a traction problem, VHT Track Bite is a liquid compound you apply to the rear tires that really makes them sticky. It’s the same stuff a lot of tracks use after an oil down.
      LMK and I’ll see if I can make a better analysis for you.
      Tommy

  9. dyneius says:

    hi I see that you are a ford man I have a 1995 ford mustang gt with 4.11 gears it has a 5.0 in it but it’s not running like I want it I have no top in speed but it runs ok in 1/4 mile we race in the streets I have 245/35/20 on it now I was thinking about going ahead and put a cam also new headers and exhaust on it to run in the 12′s what do you think would be a great setup for me? because I don’t no what cam or headers nor exhaust to get

    • Tommy says:

      Since you didn’t specify, I’ll assume you have a stock motor in your 5.0 now. Correct me if I’m wrong. You also didn’t say if you run a 5 speed or an AOD. For headers an unequal length 1 5/8″ shorty header is easy to install and remains emissions legal. The few extra horses that you get from an equal length header design is not worth the hassle when istalling or changing spark plugs if you ask me. A full-length long tube 1 5/8″ header gives a worthwhile hp + torque boost but is not street legal. For exhaust systems, I’m partial to Flowmasters myself, but there are plenty of good choices out there. Basically you want a hi-flow H-pipe and a 2 1’4″ dual system with free flowing mufflers. Flowmaster’s 40 series mufflers give you that classic 5.0 sound that I’m sure you’ve heard around town. A cold air intake is always a good addition, and adds a bit of power.

      To run 12′s you’ll need more than a cam change and headers I’m afraid. Unless you want to make the car into a lightweight track only car with a steep rear gear and slicks. But a good cam would be something like this one from Comp cams. http://www.jegs.com/i/COMP+Cams/249/35-349-8/10002/-1 A set of high performance aluminum heads would definitely be sweet to add , but are a bit pricey. These heads from Edelbrock will give you a substantial hp boost over stock, but require a few extra parts to install them on your motor. New head gaskets and head bolts are needed, these heads will work with the stock pedestal rocker arms though, so that will save you a few hundred. http://www.jegs.com/i/Edelbrock/350/60399/10002/-1.

      After that, the skies the limit of course. But with good traction you should see 12′s. If traction becomes a problem for you, see my other article on how to make your car hook for tips. Good Luck.
      Tommy

  10. Davy says:

    Hey Tommy, Been a while since we last talked. I have been considering going with a small amount of boost 6-8lbs (vortech) over the 100-150 shot of nitrous. May have to go with a size bigger injector currently have 36ers @38psi of fuel. Would it be ok to go with 8- 10lbs of boost, believe my static compression is under 10:5.1 by a little, bottom end is forged probe srs and scat kit. What are your thoughts, the cam I am running is
    http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1058&sb=0

    I did get the 4.56 gears installed finally, and the 275/60/15 nittos are running great. I have not had a chance to get to the track, think I am just going to try and build again over the winter, vortech and converter then yes.. I will be done haha! Need to find an end to this already.

    • Tommy says:

      Davy,
      Good to hear from you again, glad all is well. Cam should work fine with the blower setup you have in mind. A chassis dyno tune would definitely be needed in order to keep you out of trouble with the Vortech. This will tell you if your injectors are sufficient for HP level or if you need to raise fuel pressure. A thicker head gasket (not sure what you have now) could lower your compression ratio a bit (1/2 point). You could also add a water/alcohol injector setup (or race gas on race day) to keep detonation in check. As it will mess up your day in a hurry for sure. Bottom end should be fine (as long as there’s no detonation) of course. Sounds like you’re well on your way to the 11′s. Don’t forget to leave a bit in the budget for new safety equipment when you get there. Rollbar, single layer fire jacket required @ 11.99 or quicker. Driveshaft loop and subframe connectors also a good buy at this point.

      • Davy says:

        Yes, its nice to check in and stay in touch with a knowledgeable person as your self, thank you for everything. I will definetely head back to the dyno once its in, I normally run 110 even on causal street driving as thats usually all I keep in the tank, I will put some premium in sometimes when I get a little low with the 110-108 as I dont drive it daily, next spring may be a different story I would like to get it out and drive it more often. I am not sure of what head gasket I have now but I will for sure look into something thicker if needed then. I will stay in touch as the build comes along, I really enjoy the gears and tall tires, makes for a much smoother ride thicker tire and it being a drag radial over the hoosier, response is a big plus with the new tall gear too.

        • Tommy says:

          The taller tires also allow you to run more air pressure in them, which makes it a safer ride too. I see guys running their cars with essentially flat tires trying to get a bite. I always just shake my head and say to myself, dude get some bigger tires. Sorry the comments don’t automatically post, I had some guys spam the crap out of me years ago, so now I have to approve all comments before they appear. Sounds to me like you should be in great shape next time you make it on-track.

  11. alex white says:

    I need your help I have 91 of convert. 331 striker 5 speed tko transmission 327 gear no posi rearend drop to right side off line first time running out of gear and not getting any traction till third ran 16 reaction time.36 what do I need to do to run 12 like u said?? Thanks

    • Tommy says:

      Alex, I’ll try and figure this out for you step by step. What kind of tires do you have on the car? How big? How TALL? You probably already know that a posi unit will be in your near future if you want to go 12′s. Next thing is new rear springs (at least) , a 4 wheel set of Eibach drag springs with the airbag in the rear coil is the hot set up if you plan on racing on a regular basis. Airbag goes inside right rear coil spring and inflated (4-6 lbs. + -) until the car’s rear bumper remains level on takeoff. “Running out of gear” are you crossing the finish line in 3rd gear? What was your actual ET & MPH? 60′ time? 330′? Lets start with that info and I’ll see what I can do for you.

  12. Davy says:

    275/60/15 worked out horrible, still have the 4.10 gears in it so its time to go back to the 4.56 I suppose. Ran twice, very consistent on the 28′s but no rpms, finished out around 5500-5700 at 106 mph 13.08. Came out of the hole slow, felt slow the whole way. Do like the ride on the taller tires, feels much more stabile and easy to get out of the whole, but NO rpms it was horrible, ran twice and called it a night. Whats your thought, go to the 4.56 and should I have room for a 100-125 nitrous shot when the time comes, or go to 4.30s. Would like to run on my old 26″ but they are totally worn out. After the gear swap I will be investing in the converter, have it rebuilt and stalled higher, somewhere along 4000-4500. Went .5 second the wrong way with the taller tires. They are much larger too, very much. How would the 4.30s with the tall tire compare to the 4.10s on the small tire (26). Definately need some more gear though for those tall tires.

    • Tommy says:

      4.10′s with a 26 tire are equivalent to 4.56 with a 28 tire (same rpm). There’s not a lot of difference between 4.10 vs 4.30 (300-400 rpm). The 4.56 will up the rpm 500-700 rpm. It’s hard to say if it will be too much gear when you spray it. Depends on how high your motor can SAFELY rev…. The 28′s ARE more stable and have a much bigger footprint (more bite), BUT they’re also HEAVIER which makes them harder to get turning off the line. I’ll bet most of your + .5 seconds was in the 60′ and the 330′ times. Your combo will come together for you once you get the convertor, gear and spray all synchronized to work together.

      • Davy says:

        yes with the 50s the 60ft was 1.79 and the 60′s it was 1.89 i believe. If running 4.56 with the 28′s is the same as 4.10 with the 26′s I wouldn’t think I would have any problems then with the spray. The 50s did launch harder but thats the gear of course, back to the 4.56 it is then. I do like the 28s’ now though, they ride alot better and I would like to stick to them. I would not have any problems revving 6300-6500 with nitrous with the build (cam and springs).

        • Tommy says:

          Another advantage to running 28′s is the fact that you can run them with more air pressure in them. This makes it much safer at the top end and more stable (less squirm). Sounds like you’re on the right track (pun intended) to me. Good Luck, keep me posted.

  13. Davy says:

    Time for the test, coming up in 2 weeks. New tires are a must, looking into the 275/60/15′s, be a drag radial as I plan to drive it on the streets a little this summer and the Hoosiers were trashed after about 40 runs or so. Great tires just wear down really fast. Have a 4.10 gear still, any thought on how it will do. Nitrous will be in the future maybe late in the summer, should I stick with the 4.10s for that reason or 4.30s be able to finish out the 1/4 still.

    • Tommy says:

      Yeah those Hoosiers are pretty much a track only tire. They were originally designed for dirt track stock car racing and as such the compound is very soft. Regarding the gear change, you’ll rev the engine about 300 to 400 rpms higher with the 4.30 gears. I’m not sure how close you were to max rpm before, but if your engine can handle the extra R’s they will help accelerate the car faster downtrack. Keeping in mind if you run the nitrous your car will be going much faster (hopefully) lol. You may want to hold off on the gear change until you see how high the rpm is with the juice flowing.

  14. Davy says:

    Looks like I will be getting another radiator, still running the stock one and no heating problems but the tranny fluid has changed color some on me and I suspected that a few months ago when I changed it out, the old fluid was pretty bad. I need to pull the pan but to do so I have to move the header out of the way, so I may take this chance and look into a new pair. I took your advice and I called up hooker and they recommended 1 5/8 even if using nitrous, one thought that I have been having is I came across the hedman tork step headers, 1 1/2 step to 1 5/8 headers, would help out with torque and still have the 5/8 for flow, the rest of my setup is 2.5 piping with H pipe and dynomax bullets (resonators) open no dumps or catback. Maybe could gain some torque since I run open exhaust like that. Seen on another site they ran the same tork step design on a 383 stroker, gained hp but lost equal tq when they went to 1 5/8 so thye went back to the step style for tq. Any thoughts?

    • Tommy says:

      A new 3 core aluminum radiator will be a good upgrade for you. You should take the time (and money) now to add a tranny cooler too. The extra heat added by drag racing will seriously shorten tranny life. Use synthetic trans fluid for the better heat handling capacity. Remember that a “burnt” trans fluid loses almost ALL LUBRICATING PROPERTIES. Keep a close eye on your fluid color, if it looks brown or smells burnt, CHANGE IT IMMEDIATELY. If you have room under the car a deeper ALUMINUM trans pan will add about 2 qts. to fluid capacity. PLEASE be sure that any changes to the transmission cooler lines are made with STEEL LINES (use brake line in proper size) and NOT RUBBER HOSE. The temperature of trans fluid will fatigue rubber hoses very quickly and you don’t want a fluid leak at 120 mph.

      The header situation is a little more complicated. The DIAMETER of the primary pipes determine the powerband of the engine. Larger pipes give greater power at higher rpm at a tradeoff of torque at a lower rpm. Going fast downtrack is a product of “average power.”
      Using a step header is an effort to broaden the powerband and accelerate the car faster down the quarter. Google “Popular Hot Rodding Engine Masters Challenge” to find some really good ideas on this topic. A dedicated poweradder engine can usually use a larger pipe diameter than a similar sized NA motor. The nitrous, supercharger,turbo, causing extra air to need to be evacuated from the motor than usual. The same reason the cam would have more lift/duration on the exhaust side. The step header gives you the best of both worlds, I wouldn’t have any problem recommending Hedman headers. They make a fine product at a decent price.

  15. Davy says:

    Hey Tommy, Well got a new msd distributor put in, some new spark plug wires and got set up for a dyno next Monday, The distributor sure did help out on the idle alot, could tell from the first time it fired up, seems like it has a harder time starting at the same timing as with the old factory one but soon as its on it sure does idle soooo much smoother and doesn’t lope as hard. I’ll shoot you the results next week from the dyno.

    • Tommy says:

      Davy, It’s amazing sometimes what a difference there is between worn OEM parts and a high quality product like almost anything from MSD. Keep me posted on your dyno tune. Best of luck to you.

    • Davy says:

      Hey Tommy, That distributor was great till the moment I got to the dyno shop to have it tuned, it wouldn’t start!!! After an hr of probing around it came down to the tfi module, replaced it and no problem after that, got the tune and picked up 22hp, was totally different than previous #s but its a total different style of dyno it was one that applies load to the vehicle called Mustang Dynamometer, (http://www.mustangdyne.com/) after the dyno tuning was done for the day from the 1st reading to the last it was 42hp gain. 340hp and 330 tq. Not what I was expecting since previous #’s were so much higher but the car does feel so much more responsive and even sounds different at idle. Got it home and went to unload it and the tfi module went out again, put the one that came with the msd distributor and its been fine so far. Never been thru a module before till now. Next step is 100-150hp nitrous and be done there.

      • Tommy says:

        That’s great Davy, 42 hp is nothing to sneeze at. Try not to get hung up on the actual numbers though. Remember we’re racing cars, not dynos. Each model of dyno varies in the way it measures power output. The facts will be borne out the next time you race the car. Should be a nice improvement in ET and MPH for sure. As far as the module goes, I’ve burned through a few of them over the years. It’s very unusual for a replacement one to go bad so soon though. Was it a brand new module? Usually they go bad from the engine heat exposure over the years, must have been a defective replacement (Chinese) or something. When using the nitrous, don’t forget basic rule of thumb is to retard base timing 2 degrees for EVERY 50 hp of nitrous added. Ex. -2 deg. @50 hp, -4 deg. @100 hp, -5 @125hp, etc. AFTER you have made a few passes with NO PROBLEMS, and have checked the sparkplugs for a lean condition. THEN you can slowly add 1 DEGREE AT A TIME, make a few passes,LISTEN FOR DETONATION, check your plugs and see how it works. BUT REMEMBER WHAT HAPPENS IF YOU GET GREEDY. KA-POW lol. You also want to start with a one step colder spark plug for the basic nitrous setup and possibly go 2 steps colder when you add more hp. CHECK YOUR PLUGS, CHECK YOUR PLUGS, for they are the window into your motor’s running condition, WITHOUT literally making a window in your motor. lol

        • Davy says:

          Yeah I look forward to the next time out at the track as well, I am hoping by then to have the nitrous kit installed and tuned for it, I will have a tune for 100 and a seperate tune for 150 so that it assures me of all I have to do is change the jet. As for the module I was running a dyna mod for a yr now on my old factory distributor and never had a problem, I bought the replacement from Autozone the morning of the tune and the following morning it was already burned up, I put the module that originally came with the msd dist. and been fine since. On the spark plugs I am currently running 2 stages colder than stock recommended since I have increased compression, would I need much colder than that? I was told also that with the cam I have now that it drops power early from too much duration but with nitrous it would be ideal and extra duration be a good thing then, on the converter also to sit where I am at now and see how the nitrous pulls thru it before making a change there as I could see an increase of stall with the use of nitrous. Thanks for the response and I will continue too check the windows of the motor and to keep them in check haha!!

          • Tommy says:

            That (probably) proves my point about the module. Autozone part made in China. Spark plugs you have should be fine for starters (keep an eye on them though). More duration on the exhaust side definitely helps get the cylinders clear out when you run nitrous. Excessive duration actually lowers effective compression ratio without nitrous (this lowers power output). This is why a nitrous specific cam will generally have more exhaust lift AND duration. Larger exhaust valves and primary tubes on the headers help too on a dedicated nitrous car, My 363 cu.in. 5.0 runs a 1.625″ exhaust valve, a 2″ primary header tube into 3 1/2″ collectors to clear out the big nitrous shot. The convertor will stall/flash higher with the large torque increase from the nitrous. Run what you have now and see how it works for you before spending any more money. Don’t forget to retard the timing on the juice… You can always add more timing back in later. Better safe than sorry.

          • Davy says:

            That is one thing that I have been meaning to upgrade, headers. I have long tubes and they are 1 5/8 primary with a 3″ collector, hope thats big enough primary. Thanks for the time again and advice, I will stay in touch with the nitrous addition and gains.

          • Tommy says:

            Those should be fine for a while. Good for about 400-450 hp, then you’ll need to upsize to a 1 3/4 or 1 7/8″ header. Or if you’re rolling in the dough a “Step Header” is also a very good choice. These have a “step up” in primary pipe diameter, so at the exhaust port they are 1 3/4″ then a length of pipe and a step to 1 7/8″ into a 3 1/2″ collector. This type of header broadens the horsepower/torque curve, increasing the engine’s “average power.” Usually these headers come with adjustable length collectors too, so you can further dial in your powerband. Not sure how much effect all this has on a closed (muffled) exhaust system. Might want to consult with a few header manufacturers (Hooker, Stahl) before you buy your next set. Nothing like getting your info “straight from the horse’s mouth.”

  16. victor says:

    Thank-you very much. I’ll look further into it and do it right as I go. I has wanted a kenne bell setup, but most of the time, I won’t need that instant boost, and so I will gear the car accordingly. Will I have to run 94 octane, or can i get away with readily available 91? I expect to run a light 6 lbs boost. thanks again

    • Tommy says:

      The 2 superchargers I cited in my last reply were merely given as examples of what’s available for your car. The Kenne Bell system is actually an excellent choice for what you want to do. You can easily tune the engine to run on lower octane fuel (91) and then advance timing a bit on raceday, and use either 94 octane or drop a bottle of octane booster in the tank and be ready to go. Using only 6 pounds of boost you MIGHT be able to run regular fuel, but you may end up having to retard timing so far that performance AND fuel mileage will suffer greatly. I would say stick with the mid-grade fuel and set timing so the car doesn’t ping under load just to be safe. Engine rebuilds are very expensive….

  17. victor says:

    Great site I lucked into. Have been sitting on a 91 lx hatch w/100+miles on stock 5.0 block, garaged since 2006 and used sparingly since. Car only has edelbrock water pump, fluidyne rad, hoses, eibachs/konis/subs/swaybars. Unlike most of the drag questions you answer, I’d like to have a reliable street car i can run non-stop from toronto to daytona (19 hrs), like i used to when i first got it. I also want to be able to run 12′s in street trim, but I’m a poor almost retired guy, so I’m trying to have my cake and eat it by maximizing power, reliability and fuel economy, and minimizing risk. I was thinking of leaving the 3.08′s but using a d&d 6 spd w/ a better 1/2 ratio for takeoff, and the .50 overdrive for hwy mileage, and a blower, perhaps intercooled, long tube headers, msd6al, and whatever supporting accessories the combination requires. Is that reasonably feasible? What else would you suggest in keeping with that goal? I will also want to upgrade the brakes/wheels/tires. Thanks-V

    • Tommy says:

      Victor,
      Glad to have a new reader. I too am a poor, almost retired guy (age 52), even poorer the last few years. Anyhow, let’s see if I can help you achieve your goals. The 12′s are easily within your grasp if you choose the supercharged route. Using an intercooler is not usually required at this power level, but might not be a bad idea for a long road trip car. Helps keep temps down, although you won’t be generating much/ if any boost while cruising in OD on the highway, so temps should be okay. Any of the numerous blower kits on the market now will work just fine. So it really boils down to personal preferences as far as brands go and budget constraints of course. Typical of what’s available are items like this S-Trim from Vortech http://www.jegs.com/i/Vortech/933/4FA218-040L/10002/-1 or this one from Paxton http://www.summitracing.com/parts/pax-1001810. Both kits include a larger fuel in-tank pump and FMU (fuel management unit), but not the 36 lb. fuel injectors and 70 mm throttle body you should use to maximize power output.
      Brake and wheel upgrades can be as easy as upsizing to the 17″ wheels/tires and 4 wheel disc brakes from a ’93 Cobra or going to the aftermarket where the sky is the limit. Once again, your budget may vary. Any other questions, feel free to write again.
      Tommy

  18. barry peret says:

    great info i own 4 stangs thankyou

  19. Davy says:

    Hey Tommy, got a question for you. While having the timing set at 16 base when I would give it a little gas to around 3500 it would advanve to 35 but when I would give it gas to 6000 the timing would be at 38. When locked at 38 I would give gas and again it would go down to 35, so I set it at 40 locked and when I give it the gas to around 6000 it would again go to 38. Is that just a change cause of vacuum or would that be something else? I pulled the plugs from the track this weekend, gapped at 40 and they were super white like lean. I was running 38lbs at wot with the 36lb injectors. like you said though, get to the dyno!!! We will get there very soon. Also after its tuned and I get the right converter ordered will it have to be tuned again since the change of converter?

    • Tommy says:

      The engine vacuum does NOT come into play when the throttle is open like that. Only is a factor at small opening angles. You could also be seeing an inaccuracy in your timing light. Unless you have an uber expensive Snap On timing light, most lights aren’t that accurate at high rpm. Be careful if your plugs are pure white, add fuel pressure to prevent melt down. A dyno tune from a reputable shop is some of the best money you can spend. Most people just want to spend money on power parts and not on tuning/chassis work. Those will be the guys who you beat on raceday. It’s the whole package that wins the race, not the highest hp numbers, we’re racing cars, not dynos. Changing the convertor should not require you to re-dyno your car.

      • Davy says:

        How about crank size pulley, naturally aspirated. Does a 5′ pulley change powerband/hp or rpm rate vs a 3′ pulley?

        • Tommy says:

          It will cost you a few hp for the larger pulley 5-10or so. Not too much to worry about. The higher the rpm the higher the hp gain/loss.

  20. Davy says:

    Hey Tommy, Got a question for you. I had the timing at base 16, with the advance it would go to 38 imediately when I gave it some throttle to around 3500 to 4000 then when i would take it to 5500 or so it would go to 35 degrees advanced is that right? So I would set the timing locked at 38 like we talked about but when i gave it the gas again it would move to 35 at full throttle, so to get it to stay at 38 I have the timing locked at 40, it stays where i set it for the most but under a hard throttle it does move 2 or 3 degrees down, is that normal?

    • Tommy says:

      What you’re most likely seeing is either play in the distributor bushings, slack in the timing chain or inaccuracy caused by the factory ignition system. It’s not really made to work very well at high rpm. As rpm increases (Dwell time) decreases. What that means is the amount of time in microseconds that the ignition system has to charge the coil in order to fire the plugs decreases. This is why the MSD line of ignitions is so popular. As dwell decreases the amount of spark energy output from the coil decreases substantially. A high performance (MSD) distributor, ignition box, coil, and wires will keep your high rpm power from falling off.

  21. Davy Flores says:

    Hey Tommy, I had the timing set at 15 base and was at 38 when revved up, so I pulled the spout and set it locked at 38. responds so so much better. idle did go up and fuel psi came down about 2 psi, should I leave the idle high it’s at 1500 right now and feels beautiful. No hard start either.

    • Tommy says:

      That’s the beauty of locked out timing, the throttle response. It MIGHT crank hard when the motor heats up after a few passes. I used an ignition cutoff switch that cut the 12 volts to the coil off to prevent slow cranking. Wire it into the + side of the coil, get the motor cranking really good, then flip the switch on. It starts right up.

      Another quick tip that might cut 1/10 sec and add 1-2 mph is an alternator field cutoff switch. Wire in a switch in the field connection of the alternator (marked “FIELD” or “F” on back of alternator, the small 12volt wire on back of alternator. This deactivates the alternator and stops the drag on the motor. It’s amazing how much it really slows you down. After you’re ready to race (at the starting line) turn the switch off. Race as usual, then turn it back on after you cross the finish line, so it can charge your battery. DON’T FORGET to turn it back on, I forgot once and almost got stranded on my way home from the track with a dead battery. lol

      Almost forgot, as long as the idle isn’t making the car hard to stop when it’s in gear you can leave it be, but it might be easier to drive if you turn it down some.

      • Davy says:

        Hey Tommy, Well turned out to be an ok night car feels great and ran well but didnt gain any et. Best tonight was 42 locked timing 60ft 1.88 /330 ft 5.37/ 1/8th 8.28/ mph 84.55/ 1/4 12.87 mph 107.9 Have no idea whats going on, ran 12.6 @109 with 14 base 38 advanced, then tonight 42 locked and got the 12.8 and slower 60ft. Hooked really good, actually first time out it would launch really hard but then bog down and could feel the tire seem to be gripping different. Also the temp wasnt quiet as cool as it was 2 weeks ago here.

        • Tommy says:

          The weather definitely plays a large role in how your car will perform. Higher temps and higher humidity both make the car run slower. Perfect conditions would be cool, dry air, but not too cool because then the track is cold and traction sucks. As far as the tires go, sounds to me like you need to play with tire pressure too. (One more thing to adjust) that’s why they call it “Test and Tune” night. You DON”T want the car to “dead hook”, if it does it will cause a bog (as you saw) and kill the whole run. Ideally the tires spin once and then lightly haze for a few more feet, locking up after the car is moving good. Start adding air to the tires a pound at a time, until it starts spinning too much, then backpedal to the quickest 60′ time setup. The traction at the track varies from week to week and sometimes from run to run. Our home track sprays VHT (traction compound) once or twice a night, and if I run shortly after they do it bogs even my 9 second car down a bit. Your drop in mph is partly due to the slower 60′ time , but it might be that 42 degrees is too much for your combo at this time. Use the locked out advance set to the total timing that worked the best for you previously (38?). Now you see why I said you need to get the car to launch/60′ as best as possible, because 1/10 slower 60′ = 2/10 slower ET. 1/10 faster = 2/10 faster, etc. If you have a friend with a video camera, film your runs and then analyze them later. If you ever noticed a white stripe on the sidewall of the rear tires, that’s what that’s for. So you can see how the car hooks off the line. It SHOULD blur for an instant as soon as you leave, but not stay spinning. If you can see the line the whole time, it’s hooking too hard, so add air to the tires. More air in the tires makes for a more stable (safer) top end and reduces drag at speed. In a perfect world your tires would instantly inflate to 35 psi as soon as the car is hooked up, created a faster mph. So run as much air as possible, but still able to launch without spinning too much. Your time slips will tell you the perfect psi. Like I said before, get a notebook, start writing everything down. Fuel psi, timing adv, tire psi, right lane or left, air temp., humidity,wind speed and any notes about the run while it’s still fresh in your mind.

  22. Davy says:

    Thanks Tommy, really great advice. I will enjoy what we got for the night and head for the dyno asap, get tuned and results then see where we go with the torque converter next. The converter i currently have I belive its an 10″ and its by tci the streetfighter. I hope that converter can be rebuilt like you said, paid a decent amount for it but like you said its not for the car it was just an off the shelf part. Then after thats done, we have to swap gears again and go with bigger tires. Tires I have now are maybe 25-35 passes used so far and gears are about 3 months old and have about 20 passes as well, guess thats why its called test and tune. Live and learn but sure gets expensive.

    • Tommy says:

      Definitely use and enjoy what you have for now. Just being out on the track is the most fun you can have with your clothes on. lol Try not to get too hung up on the numbers, it will bumm you out if you let it. Just relax and enjoy the ride. Whenever you do decide to upgrade keep in mind that you can always sell/trade your used racing parts (gears, convertor) to someone else, Mustang racers are everywhere. I would run the tires you have until they are not safe to do so anymore, upgrade after they need replaced, get your monies worth out of them. A good dyno tune will pick up 20-30 hp (or more) depending how close you are to spot on now of course. Adding an h-pipe or x-pipe is good for some power too. The h-pipe tends to work better than the x at low rpm and the x picks up a bit more on the top end, your call.

  23. Davy says:

    What about running with the timing spout pulled out with full advance set? Any gain or pos/neg effect?

    • Tommy says:

      I’ve run carbureted cars with the advance locked out in the distributor before. It usually boosts the low end throttle response tremendously, but to tell you the truth I’ve never tried it with a fuel injected car. Only one way to find out I guess. Try it and let me know how it works. If it pings like crazy back off the throttle immediately.

      • Davy says:

        Does it require more fuel or less fuel when running that way? I really really appreciate the advice and talks here, I will be running this evening and really hope to improve here and come back with nothing but great talk tonight. 1 more thing, running timing locked out how does that affect/ improve the tq converter the way it will couple?

        • Tommy says:

          As long as the TOTAL TIMING advance is the same as with it plugged in, it shouldn’t change the amount of fuel needed. If it’s advanced further (more advance) then you’ll probably need more fuel. Don’t forget if the weather where you are is getting cooler now the motor will be able to handle more fuel than it did during the summertime. Raise fuel pressure 1 lb. at a time until your mph falls off (gets slower). Then go back to what was the fastest. Good luck tonight, write tomorrow and let me know how you did.
          Tommy

    • Davy says:

      Just read your other comment, thank you for getting back to me on that as well. I was just worried that I was running out of gear with that steep of a gear (4.56), also being a GT not sure how tall of a tire I could fit in the fender wells. Had some serious pull though, but still I managed to 60ft better with the current gears. Again though I had timing all wacked out of place, thats embarrasing to say though. Tuning too many things and get all lost in the mix. oh yeah.. thanks for the sea level calculation also LOL!!! We will see tonight where this converter gets us, I would be happy and settle for 11.8 to 12.2 all motor, for the time being anyways haha. What would you say a better converter would stall at for my set up? I have been told from 3800 to 4200 flash with about a 3200 -3400 footstall from 2 different places and i am footstalling now to around 2800 to 3000 and flash to 3500-3600 so doesnt seem like a big change if that would be worth the money vs say nitrous.

      • Tommy says:

        This is another reason why you need the dyno tune. You give a copy of the dyno sheet to the convertor manufacturer and they match it to the powerband of your motor. IDEALLY the stall speed should be at OR NEAR where the motors torque peak is (makes sense right). That way your car will pull out of the hole the best that it possibly can. The motor makes more torque the higher the rpm goes (within reason of course), so you might be amazed at how much difference a 500/600 rpm higher stall speed makes. Like I said before your parts setup probably has a torque peak above 4000 rpm, maybe even 4400/4500, this is where your stall speed needs to be. You said yourself it comes alive over 6000, probably not much hp down low. That’s the advantage of a transbrake also, you can hold the gaspedal to the floor and you won’t redlight. Eventually you’ll get to a point where the small brakes of the car will not hold the car still. If you flash the convertor, you’re losing time waiting for the rpm to come up and if the car stumbles even slightly you’re toast. lol Powerbraking is NOT good for ET as it preloads the suspension, twists the car all up. Remember that a Mustang GT is a fairly heavy car with a fairly small Cu.in. motor and needs all the help it can get to get moving from a standing start. In order to see the ET’s you want on motor you’re going to have to forget the streetability and go SUPER LOOSE on the convertor 4500+ rpm, get your 60′s in the 1.5′s or so. Think of an NHRA Stock Eliminator car how they run 11′s with a stock heads,intake,TB, etc. Loads of gear 4.88 or 5.13 and a 8″ convertor. They 60′ like a beast and go really quick with less than 300hp, chassis worked to the max to make up for lack of serious hp.

        With the proper wheel offset (I used a 15 x 8 wheel with 5.5″ backspacing and some judious hammerwork on the INNER fenderwell I managed to fit a 10.5 x 28 ET Drag or 12.5 x 28 ET Street (same tire just measured differently) inside the fenderwells. Slicks are measured at the tread width, ET Streets are measured at the sidewalls (overall width). M&H Racemasters also come in a 27″ height too.

  24. Davy says:

    60ft 1.79 — 330ft 5.24 –ET @ 594ft 7.62 –1/8th et 8.15 mph 85 1/4 12.68 mph 109

    Long tube headers, dynomax bullets resonators, stock fuel rails, 190lph pump, 36lb injectors regulated @ 36-38lbs on the rail. Never been on a dyno for tuning before but went for a fundraiser before, 400hp and 420tq to the wheels. This was when I had 4.56 gears though and a typhoon products upper and lower intake 70mm tb, since then changed to holley systemax intake, 75 mm tb and 4.10 gears. Got the tranny fluid changed out, sure does feel alot better nice and firm, no slippage anymore. Thanks for the response and tips

    • Davy says:

      actual #s were 399hp and 445tq had to get out the dyno sheets, but like I said it was just for a fundraiser, and it didnt read a/f or save rpms for the printout. just an idea for you though. In the future I do want a custom tune for at least dyno tune for max hp, dont really look into get any kind of other electronics computer or anything for it, maybe a chip but thats as far.

    • Tommy says:

      Your Welcome

    • Tommy says:

      Very decent numbers you have so far. Looks like you do have some room to improve your ET and mph here. Car appears to be slowing down in the second half of the track (not literally). The general rule of thumb is you take your 1/8 mile ET (8.15), multiply by either 1.54 (optimal setup) or 1.55 (average car) and it should equal your 1/4 mile ET. So 8.15 x 1.54 = 12.55 and 8.15 x 1.55 = 12.63. What this formula does is tell you if you’re faster (quicker) in the first half of the track or the second half. If your 1/4 mile ET was lower than a 12.55, I would say your car is probably going like hell in the top end and probably not 60′ footing very well. Your car is just the opposite of this, it’s going good in the first 1/8 and (I’m guessing here) probably leaning out in the second half of the track. Does your car feel like it pulls well till the 1000′ mark and then feel like you can’t wait for the finish line to get here (straining or slowing)? How tall are your drag radials? Could be running out of rpm due to too low a gear??? Your 60′ is definitely respectable, but a better convertor (and transbrake) will cut a lot off your time. Remember every tenth you cut in the 60′ equals (at least) a couple tenths in your 1/4 mile ET, gains compound as you go. Do you street drive your car? If not stripping as much weight as possible out will lower ET’s as well. Every 100 lbs. = .12 seconds off your ET. I know 100 lbs sounds like a lot, but it’s really not, the old saying goes “What’s the best way to lose 100 lbs.? look for 100 places to lose 1… I took the bathroom scale out in the driveway when I first started racing my red car and was amazed how much weight I saved.

      • Davy says:

        275/50/15 hoosier drag radials. Car feels like it comes out of the hole ok, but really feels like it comes to life at like 6300 to 6500, feels like a whole lot of power just comes on at that time. not sure the weight of the car but i have stripped quit a bit, no ac, power steering, heater, skinnies up front 15×8 in back, fiberglass hood, tubular k member and other susupension as mentioned before. I am running royal purple 5w-30 in motor, supershift not in the tranny and royal purple gear oil in rear end. I do have a uego a/f meter and it reads 12.8-13.2 at top of the track. What kind of rpm for a converter would be ideal, still somewhat streetable. current converter is 3-3400 advertised stall and i am well at 3500 at launch. tires dont break loose no issue there what so ever. need more fuel? timing is at 15 degrees, advanced i believe its like at 30 or so and I run 110 octane and had the best mph with that low of timing.

        • Tommy says:

          275 tires are basically 26″ tall, with a 4.10 gear that means 5800 rpm +/- at 109 mph, that’s good. 12.8/13.2 AF ratio is good too, 30 degrees timing is pretty low, most 5.0′s run best with 32/34 degrees timing in them. Get a timing tape (goes on balancer) so you can know for sure what your timing is set at. Rev the engine up to 3000 rpm and using a timing light see where it actually goes to. Have you tried running more timing at the track? More advance will lower your 60′ time, it might make your mph slower, but lower your overall ET (might). Only one way to find out for sure. The road to a fast car is experimentation. Change ONLY ONE THING AT A TIME, then test it for 2-3 passes and see what happens. Advance timing 2 deg. test, advance 4 degrees test, adjust fuel pressure up 1 lb, 2lbs., etc. test. LOWER fuel pressure 1 or 2 lbs, test, and so on. You may find that a COMBINATION of lower/higher fuel pressure works ONLY with more/less timing, this is where a good dyno tune comes into play. Instead of thrashing your car all weekend at the track, you can get it right in a few hours with much less wear and tear on your car. Get yourself a logbook and write everything down, so you don’t get confused and forget where you are. Remember cooler air (Fall weather) means your car can handle more fuel/timing than during the hot Summer months. For a convertor it’s up to you how loose you can stand for a daily driver. With your parts combo, 282 cam, 190 heads you do have a high rpm combo for sure. You can buy an adjustable timing chain set and advance THE CAM by 2 – 4 degrees too, this will lower your powerband by several hundred rpm and boost your bottom end torque.More gear would be in order if you didn’t street drive it (4.30) but would make your bad gas mileage even worse. lol Don’t forget a tranny cooler, because all that slippage definitely heats up your fluid. I still stand by my dyno tune recommendation, it’s possible that you have lean/rich spots in your fuel curve with all the parts you’ve changed, a custom computer chip can make a world of difference.

          • Davy says:

            yeah i almost wished I had gone with the 4.30 ratio instead, i had 4.56 and liked them alot but felt that i was running out of gear on the 1/4, also bad news was that i was at 35 degrees timing with out advance then with the advance it would only go till around 40-42, I never realized that till i got the 4.10s in and i decided to pull some timing out for trade of some top end power. Who knows what could of been with correct timing and 4.56. I think the same thing as you, I really need to get it tuned on a dyno, I will see what I can do here soon. Track is coming up this weekend and its the last of the season here so I will have plenty of time then, I am trying the type F fluid hoping to gain a little higher rpm stall and more positive shifts thru the gears hoping I can get away with that to gain rather than doing the whole converter over again. I will try 1 thing at a time this weekend, start with add 2 deg. timing, how will fuel pressure change with timing, will I need more fuel or is that just one of the things to look for. According to the tci site for this converter its top end power. Not sure if I have a mismatch converter for engine and need something different, just did it once already and it was a task for sure. Not to worried on gas mileage either, this vehicle rarely sees the streets. more of a show car that I really like to race. Just really wanting to get low 12′s so bad all motor or 11′s if possible. Last time out at the track, each time I pulled timing 1/4 et’s got faster till I hit 14, 16 was the best so I am at 15 for now. 16 degrees was almost identical to 14 degrees with an additional 8lbs of fuel at 14 deg timing 60ft was 1.78 1/8th 8.18 @85.56mph 1/4 12.70@109.16 same mph as 16 timing less 8lbs fuel though.

          • Tommy says:

            Eventually you’ll probably want to go back to the 4.56 gear with a 28″ tall tire. My red car ran with that setup and did very well. The taller tire gives you a longer footprint on the starting line increasing traction. The other thing that I’ve used is a timing retard box for the ignition. Not sure how you hook it up for a fuely car though, contact MSD for the right parts/instructions. With the retard box you run a ton of timing in first gear where the engine can accelerate faster because of less loading on the motor.It is connected to the shifter by a micro switch, when you shift into 2nd it retards the timing a bit, for better top end mph. They also make 2 stage retard boxes so you can retard the timing even farther in high gear. You adjust the amount of retard in degrees with a small chip set (like the rev limiter chips) they only cost a few dollars for a set. This will give you even more tuning options and will require some track time to figure out which ones work best for your combo. Aftermarket FI systems (computers) allow you to set these numbers with a laptop.
            The torque convertor can be cut open on a lathe and the stator replaced inside to give you a different performance characteristic without buying a completely new one. This will need to be done by a professional trans shop as it needs rebalancing afterwards.
            The easiest way for you to hit the low 12′s is to run the car at sea level. lol The NHRA altitude correction factor for 3600′ to sea level is X .9562 ET and X 1.0465 for mph. This would put your car at 12.68 x .9562 = 12.12 ET and 109 x 1.0465 = 114 mph.

  25. Davy says:

    Also forgot 36lb injectors, pro-m80 meter 36lb tune. pressure at 36-38, autolite 3924′s at 40gap, crane hi-6 ignition with lx 91 crane coil. Had champion same temp plug but gapped at 45-47, went with autolite and smaller gap hoping for little more tq, also trying out some type f fluid in the tranny since it has been rebuilt kevlar clutch and servo changes.

    • Tommy says:

      Next oil change switch to full synthetic oil, it greatly reduces engine wear and can cut as much as a 1/10 of a second and add 1 or 2 mph to your topend. I’ve had great success using Mobil 1 fluids, engine trans, rearend in my car. It’s well worth the extra money you pay and more than makes up for it in extended equipment life. Adding a transbrake will allow your car to get all the stall speed potential out of your convertor and make your car launch like a stickshift car. Now would be a good time to add one, if you just rebuilt the tranny.

  26. Davy says:

    Awesome site, its set as one of my favorites. Got a 92 gt with a 331 in it, 190 pro comp heads, xe282 comp cam, 10.5 compression, 4.10 rear with adjustable upr weld in anti rollbar, tci streetfighter converter (32–3400) but i see it flash to 3600 at the track. Tubular k member, tubular rear uppers and lowers, tokico adjustable struts and non adj rear shocks. Power steering, ac and heater, smog removed. Holley systemax 2 intake 75mm tb and 1′ intake spacer. I do got the transgo kit as well, no line lock or trans brake. elevation is 3600 here. Best time so far has been 12.6 @109 60ft 1.78 on hoosier drag radials. What would be your expected time out of this combo, I thought it would be better than this. Atleast 12.0. What could i do for tuning or what would you suggest changing or looking over? Thanks for you help and advice

    • Tommy says:

      Thanks for bookmarking my blog, always glad to have new readers. You’re right about your combo being capable of much greater things. Being at 3600′ definitely costs you some power, however. Your car seems to have some decent HP, in order to run 109 in the quarter your car should be able to run low 12′s or high 11′s, let’s see if I can help you get there. Is there any place that you can take your car to with a chassis dyno? I’m thinking off the top of my head that your car is probably leaning out in the midrange (rpm). What kind of fuel pump, what size fuel lines, and filters? With all the parts you added, your stock fuel/timing curve is bound to be out of whack. I’ve seen some serious power increases from a few hours on the dyno, so it’s worth the drive to the city to find one. What type/size of headers are you using, short/long tube, X-pipe or H-pipe, mufflers, exhaust pipe size? Next time you write, tell me your interval times/mph on the rest of your best ET slip, 330′, 1/8 mile ET & MPH, 1000′, 1/4 mile and any other info they give you on the slip. That will help me diagnose what’s happening here. Race Safe.
      Tommy

  27. zac says:

    Hello, I asked you some questions a while back Tommy. I finally got my car to the track and man it was the SHIT I ran 11.68 my first ever pass in the car went to the pits adjusted the coil overs and layed into it hard 4th pass with the best of 10.89 on a little juice. Thanks for all the advice and all the people that helped me along the way o yea she’s a 347 solid roller with cnc’d 190 canfields now

    • Tommy says:

      Your welcome Zac, glad to be of help to you. That sounds really great about your car, it’s lots of fun when you finally get it all together like that. Congratulations are definitely in order. If you have any pictures you want to post LMK, I’d be more than willing to put them up here for you. If you’re interested in writing a short story about you and your car and include some pictures, I can give you your own bragging rights page. It always makes me feel good when someone I’ve helped does so well at the track. Keep me updated from time to time on any future improvements or additions. Race Safe.
      Tommy

  28. Adam Grover says:

    not hard to build a 12 second car. bought my 1980 mustang notch for $200. i already had a 88 5.0 roller engine. bought a weind dual plane intake a 650 holley long tube headers H pipe spintech mufflers. car was stock weight with open end 3.08 rear c4 trans with a stall converter from lupo dynamic. car went a 12.97@104 mph. i then had the converter advanced to newer technology and changed some things like suspension and weather temps outside dropped down did some timing and the car went into the 12.30s on motor. i have since done some other things 1.7 roller rockers electric water and took off the power steering pump. cant notice a difference yet because of weather change but the car is 12.30s in the heat where before was 12.50s. expecting for it to drop into the 12.20s to 12 teens possibly even 12.0s. im shooting for 11s with stock heads stock cam stock bottom end.

  29. Calvin says:

    Your site is kick ass!! I have an 89 GT mods are stock forged 302,holley 650dp,torker 2 intake,gt40 heads w/crane 1.7s TFS springs,b303 cam,holley blue fuel pump ,msd ign ,elec fan,long tubes,hpipe,dumped flows,3.73s,big n lils 15×8 rears w/275/50 nitto drs,strange adj shocks,eibach drag springs,wild rides upper &lower torque boxes, bbk upper/lower control arms,subframes,RAM hdx clutch,T-5, zex 150 shot. Haven’t been to track or dyno yet.what do you think she’ll put down on the dyno with and without spray and what you think it’ll run?

    • Tommy says:

      Thanks for the good words. Your GT if it’s full weight (No stripping) should probably be able to crack into the 12′s on muscle and 11′s with a 150 shot (IF) the traction is good.
      If you hit 11.99 or quicker, you’ll need a 6 point roll bar and a single layer Nomex jacket in order to keep racing, so put that in your future budget plans.
      You might consider pulling off the front swaybar if you race it a lot ( helps the front end lift and loses 30 lbs. of the front of the car too). Leave the rear bar ON the car, it’s necessary to keep the car from squating in the right rear corner when you takeoff.
      If the right rear still squats, you need to make the right side shock stiffer until the rear bumper is level on takeoff.
      Having somebody with a video camera behind your car at the starting line will be a big help.
      That way you can review your runs after you get back to the pits. Make any needed adjustments, cool off the motor them get back in line.

      A good dyno tune is definitely a big help when you first put a car together. Helps you get the timing and jetting set without wasting a lot of time at the track.
      That way when you finally do get there, you’ll kick some ass. As far as a dyno number, keep in mind that chassis dyno numbers are always a lot lower than most people think they should be.
      Because you have about a 15-20 percent loss through the drivetrain.
      Keeping that in mind, you’ll probably be somewhere around 300hp (at the wheels) on muscle and it’s up to you and the dyno guy on whether you spray it or not on the dyno.
      But a 150 shot should bump you up around a 100 more or so.
      Good luck and race safe. If you have any more questions, don’t hesitate to ask.
      Tommy

  30. zac says:

    hi i have a 88 coupe and im trying to get into my local bracket club ive installed my cage and curently working on my engine and suspention ive built a 306 with i canfield 190s ported and polished 2.05 1.60s victor intake and 650hp carb with tfs stage 2 cam stock bottom end basicly 9:1 comp on a 125 shot bullet c4 with brake and a 3800 stall draglites and 28 x 10 x 15 m/t et drags 90/10s up front with bbk control arms uper and lower with bags in the rear just trying to figure up my combination any advice o yea 4:10 with a spool

    • Tommy says:

      Sounds like you have a nice group of power parts here. The 190cc heads are a little big for a 306, but at least you’ll have plenty of room to grow into them. lol
      A couple questions to get me going, before offering my advice.
      What is the main usage of the car? Street/strip, Track only, more street than strip, mostly track etc…
      What do you have for headers, ignition parts, fuel pump(s),?
      When you say (Victor) intake, do you mean “Victor Jr. or Victor?”
      Have you run the car yet, or is it still a work in progress? If it’s been down the track, what were the times/speeds?
      Do you have access to a dyno tuning shop in your area?
      Have you drag raced (any) car before?
      LMK, and I’ll get back to you ASAP.
      Thanks
      Tommy

      • zac says:

        thanks tommy its a victor intake and its a track only car completely gutted i have bbk long tube 1 3/4 primarys with 3 inch collector open no muffle i have 3/8 braided fuel line with a holly black pump with aromotive pres. regulator set at 9 psi drove the car this morning played hooky and skipped school to get a little time with it finally got my carbed tune with a wide band o2 sensor i havent took it down the track yet but planning on it to be soon ”within 2 weeks” and i have drag raced before but with my friends door slammer only a hand full of passes 704 bbc with a glide 4.89 at 139 broke a rocker strait off the head but thats all it took im an adict now lol this is my first race car build and plenty more to come thanks for your timely reply

        • Tommy says:

          Zac,

          Be very careful with the stock bottom end. They say 500 hp is safe, but I’ve seen them blow with a LOT less.

          The upper rpm level is just as bad as too much hp, so keep your redline to about 6500 rpm or so until you upgrade rods, pistons, crank etc.

          Your choice of parts is sounding better all the time.

          You’ve got some room to grow into for sure.

          Like I said before your choice of heads, intake and headers are a bit too large for only 306 cubes,

          your bottom end will probably be a little soft, but should pull like crazy over 4000-4500 rpm.

          but are gonna work like gangbusters once you up the cubes/turbo the beast.

          A good dyno tune is the way to go if you can afford it. A few hours on the chassis dyno can tell you as much (or more) than a month at the track.

          Make or buy yourself a pair of 3″ collector extensions about 18″ long or so, if you plan on running with no pipes.

          It will bring your average power up dramatically and you can always cut them a bit shorter if need be later.

          Or you can use an H-pipe or X-pipe by itself for a bit more bottom end.

          Jegs has a set of carb jets (I have these)
          http://www.jegs.com/i/Holley/510/36-181/10002/-1

          So you can adjust your fuel ratio to what it needs to be.

          If the dyno shop sells jets right there, you can always use theirs instead.

          A 1″ or 2″ carb spacer 4 hole can also be used to adjust your powerband.

          Maximum power will probably be with around 32-34 degrees TOTAL timing in the ignition.

          You’ll want to recurve the distributor to get around 18 degrees at an idle, with the rest in by 3000 rpm.

          Keep an eye on your sparkplug color to be safe. If the porcelain is pure white it’s too lean or plug is too hot.

          Back off the throttle IMMEDIATELY if you hear any detonation.

          THIS will kill a stock block motor PRONTO….

          Some high octane race fuel in the tank wouldn’t hurt you either. Don’t get nuts and buy the 112 octane for now, but the 100 octane stuff isn’t bad for a 9:1 motor like yours.

          I was going to tell you that a 28″ tall tire on a 306 will work better with even more gear on a track only car 4.30/4.56.

          BUT if you plan on adding a lot more hp, then I would say stick with the 4.10′s for now.

          Is your tranny a AOD or a C4?

          Does it have a transbrake?

          If not then you need to put one on your wish list.

          It allows a auto car to launch like a stick/get the full 3800 stall from your convertor, greatly reducing your 60′ time.

          BUT the tranny/suspension has got to be built to handle the abuse of course.

          Your car should run just fine the way it is now.

          Listen to me spending all your money for you. lol

          Have fun and LMK how track day goes.

          If you have any specific questions for me, just ask.

          Always willing to help a fellow racer and Ford man.

          Tommy

          • zac says:

            thanks your very informative i have a brake in my c4 with a hardend shaft reverse valve body red alto clutches and new planetaries from a friends x275 radial mustang freshly rebuilt

          • Tommy says:

            That should work great, sounds like you have everything you need. Now a few test and tune sessions and a little seat time and you’ll be kicking butt.

      • zac says:

        sorry i have a msd billet dist. and a 7al with the 2 step 10mm wires and there is a dyno shop about 4 hours away bb&t racing in mississippi when i can get most of my bugs worked out im pulling my car there to get a session in just to see what im working with im worried about the factory block holding up also they say there good to 500 and soon im going with a 76mm pression turbo blow threw setup with a c&S carb then im buying a R block stroked to a 331 if you think its a good idea

  31. Craig says:

    I have enjoyed your site. I have a 93 302/AOD convertible stock stang. I am going to start doing work to it and get it more enjoyable to drive. Right now it has very poor performance but looks great (Yellow w/black leather and black top w/ 40k miles). Although it looks great, its embarrassing how it performs.
    I want to keep the dependability so I’m thinking of header exhaust with no cats, swapping the tall gears for 393′s and cold air intake to start. I also will be looking to improve suspension and stiffen it up. Light motor work will be in the scope also, but not sure what direction to go.
    What would be your suggestions on where I should start as I want to be able to drive time to time during progress of my project car?

    Thanks in advance
    Craig

    • Tommy says:

      Thanks for the compliment, glad to be able to help you. First things first, the rear gears (3.73′s) are an excellent choice for an AOD equipped car. While I’m on AOD’s a nice performance shift kit (Transgo PSK kit), will firm up your shifts nicely and prolong transmission life. Be sure and change tranny fluid regularly, if it gets brown and smells burnt (at all) it will severely reduce trans lifespan. If you’re going to remove the cats, then you should definitely go to a 1 5/8″ LONG TUBE header. The torque difference between a long tube and a short tube is worth the extra cost if you ask me. To go with your headers an H-pipe or X-pipe along with a free flowing exhaust system and mufflers complete the package and give you that trademark 5.0 SOUND. I’ve always been a Flowmaster guy myself, until I bought the Borla Extreme system for my wifes 2000 GT, ( both systems work great). But there are plenty of high quality systems out there and buy whichever one you like/can afford.
      Next I would buy a cold-air intake system to reduce inlet restriction, DO NOT buy a larger throttle body or mass air at this point in time. (No matter who tells you, you need one). The original pieces are large enough until you start making a lot more power and provides almost no improvement on a near stock engine. Your budget and intended usage will determine where you go after these parts are installed. Good luck with your project, sounds like a great Stang you got there. Tommy

  32. James says:

    I have moroso trick front springs(250) rate but I have new stock type struts. Will the springs help with weight transfer with the stock struts or are drag struts a must? I hate to throw the struts aside they only have 400 miles on them

    • Tommy says:

      Of course drag specific struts would be best, but your stock struts will work too. Best to try it out at the track first and see how well she transfers the weight before spending money on new struts. Removing the front swaybar will allow faster weight transfer. Video taping your runs can teach you a lot about how your car launches. It’s hard to judge exactly what is happening from the drivers seat. If you ask a friend to watch for you. You get comments like “The car looked good” or “It was badass man”. lol Not exactly valuable information. With a video tape, one or more filmed from the side and one or more filmed from directly behind the car, you can see front/rear weight transfer, wheelspin, and body roll (twist) from behind. You can also compare early testing runs to later passes to see the inprovements you’ve (hopefully) made.

      You want the front end to rise quickly and smoothly, a very short spin of the rear tires ( a turn or two, no more) will help keep the motor from bogging, lowering ET. From behind, the rear bumper should be flat horizontal (parallel to the ground). If the right rear corner is dropping, it’s unloading (taking weight off of) the right rear tire. Airbags in the rear coils (with separate fill lines, more air in right side bag) or an adjustable rear swaybar will work to level the car out. Doing this equalizes rear tire marks (traction) and keeps the car from driving to one side (pulling) under power. You can actually find the right air pressure difference or swaybar adjustment on clean dry (isolated) pavement somewhere. Start with 4 pounds in each side and do a few launches and keep adding air to the right side until tire marks are the same length. If using an adjustable swaybar, shorten right side end link to shorten right side tire mark. Adjust until equal length marks on ground.

  33. Jason says:

    I have a 90 GT with the followin upgrades; GT 40 heads, GT 40 intake, BBK long tube headers with H pipe and flowmasters; Full MSD ignition, 36lb injectors, Pro-M cold air; 70mm throttle body, Steeda 18 cam, 3.73 Richmond gears, Tremec T-5, King Cobra stage 2 clutch, Steeda stages 1,2 and 3 suspension upgrades and frame stiffners, 17″ cobra R rims with small 245/45/r17 tires. what should i expect my car to run with this set up?

  34. Jason says:

    I have a 1990 GT with GT 40 heads. GT40 intake Steeda# 18 cam, MSD full ignition, BBK longtube headers, H pipe, flowmasters, Tremec T-5, king cobra stage 2 clutch, Steeda stages 1, 2, 3 suspension updgrades, 3.73 Richmond gears and frame stiffners…I can’t get my car to hook i have Cobra R rims now and wondering what should i expect with this set up in the 1/4 mile and what other mods (except for tires) can i do to increase my time?

    • Tommy says:

      Not familiar with the Steeda cam personally. Specs sound similar to a Ford B303 cam. Steeda’s website says their car ran an 11.90 @113 mph with the GT-40 Drag pack, whatever that includes? Could’nt find a list of their parts used for those numbers. Although I have a feeling the car had a drag racing type suspension AND drag race specific tires (ie slicks) on it. What tires are you currently running? If you have your typical street type low profile tires on your car, it will SEVERELY limit your ET’s. Might want to consider buying a cheap set of spare rims (15″) and a pair of Mickey Thompson ET Drags in 8.5 x 26-15 if you really want to optimize the car for the dragstrip. Nothing will be quicker than slicks, drag radials will work, but slicks are the ultimate tire for a drag car.

  35. Ty says:

    i have a 1986 t-top gt full drag car it has a 302 roller motor basically stock bottom end just h beam rods main girdle stock bore the heads are off a 67 high pro 289 fully worked over ported polished 194 160 valves 1.6 rockers f-303 cam and 750 demon carb 100 shot nos. tranny is a performance automatic c-4 4000 stall and trans brake line lock all the suspension goodies 456 gears have not ran it with the nos yet we only have an 1/8 mile track here its curently running between 6.99 and 7.10 with a 60 foot at 1.350 and mid to high 90s at the finish hoping for 6.5s with the nos

    • Tommy says:

      The formula for converting 1/8 mile to 1/4 mile ET is 1/8 mile ET x 1.55 = 1/4 mile ET. Given your 6.99-7.10 1/8 mile et now equals a 10.83 -11.01 1/4 mile et. To get to a 6.50, 6.50 x 1.55 = 10.07. I don’t think you can make that big of a jump without rethinking your entire motor. An almost one second et reduction from where you are now will require 150-200 more hp than you have now. While new race type large valve aluminum heads, a radical solid roller cam and 12:1 or more compression would be a big step in the right direction. You’ll also still need to add about 75-100 hp more nitrous, which would take your stock bottom end to the scrap pile (no offense). It’s just not built to withstand that kind of strain on a regular basis. A 4 bolt main race built 347 with the above mentioned parts will get you there RELIABLY. After all we’re building a racecar, not a hand grenade. Sorry

  36. James says:

    My funds are low at the present time. Could I improve my traction with some 50/50 shocks out back and 90/10′s up front? And also would the frpp “b” springs work well with the 90/10′s until I can upgrade the front springs?

    • Tommy says:

      NO
      Any of the lowering springs (from anybody) are too stiff to work the suspension for a good takeoff. For my red car I used 4 cylinder Mustang (85-86) WITHOUT A/C front springs. You can order them from NAPA or elsewhere. A low budget alternative, that has thinner coils that transfer weight and LOWER the front end as well. Depending on the frontend weight of your car you may need a spring spacer underneath or have to cut a 1/2 coil or so off (less likely). You won’t know for sure until you bolt them up and try it.

    • aj says:

      Me and my brother bought a 1993 5.0 foxbody ,it was fuel injected and somebody carbrated it and cut a crap load of wires on it so now almost none of the electrical works on it but we still wont to keep it carbrated. What should we do?

      • Tommy says:

        Locate and buy the Ford Service Manual for a 1993 Mustang. Get the “electrical system volume.” It will have all the wires listed for you, lots of diagrams. After that you’ll probably want to purchase a new “underhood” wiring harness, if it’s been butchered. If damage is minor, you MIGHT be able to repair it. But you’ll need to solder all the connections and then heat-shrink tubing them, so you don’t start a fire and burn your car to the ground. It happens on cars where the wiring is rigged. DC current is nothing to fool with, very unforgiving of sloppy work.

  37. James says:

    My car did not perform very well in the traction department. It spun and I really couldn’t leave the line at much above an idle. I’m sure it has alot to to with the slight drop on it. (1/2 rear, 7/8 front. I’m thinking of using 90/10′s up front along with trick front springs or either eibach drag launch springs and running my sway bar while I street drive it. I don’t want the front end end way up in the air though. I would greatly appreciate your advice on this subject. Thank you.

    • Tommy says:

      Lose the lowering springs NOW. The worst things you can have on a drag car, they are way too stiff to allow your suspension to react. If you plan on racing the car I would use the Eibach drag springs or even the stock springs, they’re better than the lowering springs. If the car sits too high for your liking you can cut a 1/2 or whole coil off with a 4″ angle grinder and a cut-off wheel, DON’T USE A TORCH. I would resist cutting the springs if at all possible, cutting them negates some of their advantages. Strut change at the same time will mean you only need to pay for one front end alignment. Disconnecting the sway bar (FRONT ONLY) on track day will also help. DO NOT remove the rear bar EVER. It helps to keep your car level on launch. Move the battery (in a NHRA approved box) to the right rear of the car will put more weight where it’s needed and help to lessen the nose heavy weight bias of the stock GT.

  38. Tyler says:

    ive never been to a track and im wondering what an estimate time would be i have a 347ci stroker, gt40 heads, b303 cam, edelbrock high rise intake manifold, edelbrock 4barrel carb, pete jackson gear drive, and 3.73 gears, hopefully come may ill be purchasing lakewood upper/lower control arms and traction bars, bbk long tube headers, and 4.56 gears. would that be a decent car? and any clue how good lakewood control arms are?

    • Tyler says:

      and its n lx not a gt (93)

    • Tommy says:

      Last question first, I’ve never used the Lakewood bars on a Mustang, but their products are usually high quality and should work fine for you. Using a 4.56 gear which is what I used in the red car, you’ll need to go with a taller rear tire. I used a 9 x 28 ET Drag slick on my Stang, otherwise you’ll overrev before you get to the finish line. A taller tire will give you more rubber on the ground and better traction too. I’m assuming you have a 5speed in your car? AOD? Low 12′s should be within your grasp with these mods and good tires. What size carb is it?

  39. James says:

    I have an 87 Gt. It has a 308 with windsor jr. heads custom grind 507 comp cam with ported performer 5.0 intake and an accufab 70mm TB. It also has a cai with a Pro-M mass air. Long tube headers with H-pipe and full exaust. It is a 5-speed with a centerforce clutch and 3.73′s. Tires are 275/50/15 555R’s. Is it possible for this combination to see 12′s in the quarter?

    • Tommy says:

      Have you been to the track yet? What did you run? The Gt is heavier than the LX and a lot heavier than the coupe, however 12′s are definitely possible with some test and tune work. Your car has some good motor pieces, but no chassis mods. Time to work on the suspension. I always use the example of NHRA “Stock Eliminator” to point out how fast you can go with limited horsepower.
      By optimizing the chassis to use the hp you already have, you’ll spank the guys whose cars are less well prepared. The secret to a quick ET is the launch/60′ time. My red car has 60′ in the 1.6′s with less than 300hp. This is what got me in the 12′s and will be your secret too. You need to be able to side step the clutch at 4 grand and then hang on to get to these numbers. Car must be able to dead hook on a frozen lake I always say. lol
      Upper and lower control arms, drag springs, shocks and struts, welded in subframe connectors, unhook front sway bar for starters. I know most people hate to spend money on things they think won’t make them faster (non-motor mods) but this is EXACTLY what will make you quicker/faster. Then get in the burnout box and heat up those tires. Then practice,practice, practice. Test and tune night on an off night (Weds here in Fla.) gets you more runs down the track then you’ll get on Friday or Saturday when EVERYONE goes. Not to mention it allows you to get the kinks worked out without all eyes watching.
      Around this time is when I usually recommend you buy a Line-Loc so you can properly heat your tires. Insufficient heat in the tires is the number one reason people say my car with DR’s spins the tires. That and improper suspension mods (lowering springs) get rid of them if you have them. After all there are cars running in the 7′s on DR’s (275′s even) so yours should hook no question…

      • James says:

        I did forget to mention. I have aftermarket upper and lowers with new springs and subframe connectors as well. I also have a 125 shot but I’m just curious as to what I can run without it. I will also be taking the front sway bar out. Does removing the rear help any?

        • Tommy says:

          NEVER remove the rear bar. As a matter of fact my green car 9 second Mustang has 2 rear bars on it. The factory bar and an aftermarket one from Competition Eng. The rear bar helps to keep the rear of the car from rolling over (not literally). If you’ve evr watched a car leave the starting line all twisted, with the right side of the car lower than the left, you know what I mean. Ideally your rear bumper should be parallel to the ground (level). If it’s not then your car is putting more weight on one side of the car than the other. This unevenly loads the rear tires and can (will) make the car drive towards the guardrail on the side of the track (very bad) ;-) . Have someone video tape your car from behind at the starting line to see if your car does this or not. If it does you can add an airbag inside the right rear coil spring and gradually add air to it until your bumper is level on takeoff. You can also tighten up your adjustable shock on the right side, if your car has them. Launch the car on clean, dry pavement and check the black marks on the road. Add air to the right rear bag until they are of an equal length. This may (will probably make your car sit uneven (out of level) when the motor is not running. A small price to pay in order to kick ass at the track. If it bothers you, you can lower the air pressure when you’re not racing. My car has 2 airbags (one in each side) so I can adjust ride height as well as suspension preload. Using an adjustable rear sway bar (aftermarket) will also allow you to do this.

          • gabe says:

            I have 88gt convertible trickflow upper lower b303camb 24pound injecters long tube headers h pipe 373 gears under drive pulleys would a zex wet nitrous 125 shot be OK

          • Tommy says:

            How many miles on the motor? Is it a stock bottom end? I usually recommend starting with a small nitrous shot 50-75 hp and working my way up from there. While it may be able to handle the 125 shot, it might not either. By starting slow and seeing how your motor handles it, you’ll be able to get more than one run out of it before it blows up. lol Base timing needs to be retarded by 2 degrees for every 50 hp added. (2 deg. for 50hp, 3 for 75, 5 for 125 etc.). Stock spark plugs should be fine for the 50 or 75 shot, but you’ll probably want colder plugs once you get past that hp level. One or two heat ranges colder should do it for the 125 shot. Keep an eye on the color of the plugs and adjust fuel pressure higher if they’re bone white. Should be a nice off-white / tan color. If the electrodes are turning blue on you STOP RIGHT THERE, you are getting ready to do MAJOR DAMAGE to your motor. Retard timing, colder plugs or more fuel is required NOW, before using the nitrous again. The other thing you’ll want is a larger fuel pump and adjustable pressure regulator to supply the added fuel on nitrous. I would install the pump/regulator before using ANY NITROUS. It’s what they call cheap insurance. Be sure and follow all the directions included with the kit and DON”T CUT ANY CORNERS. Nitrous is a easy, fun way to add hp to your ride, but tread lightly and you’ll get to enjoy it without doing damage to your motor. Most people who blow up their car do so by adding too much, too fast.

  40. Billy says:

    I don’t have a track close by and was wandering if you think my Foxbody is capable of 12′s. It has a 306 with Windsor sr heads and 507 lift lunati cam and 1.6 roller rockers. I have a tricklow upper and lower intake with 24lb injectors and a 70mm throttlebody. The exhaust is bbk shorty headers with a h pipe and flowmasters. It has a t5 trans with 4.10 gears and I also have nitto 555r drag radials.

    • Tommy says:

      It sounds to me like you should be able to reach the 12′s easily with your combination. It all will come down to how well you can launch your car from the starting line. You might want to consider some suspension mods to take advantage of your horsepower increase. Aftermarket rear lower control arms will eliminate wheelhop. Drag race style shocks and springs aid in weight transfer, as will removing the front anti-sway bar. Check out my blog article here for more tips to get you solidly into the 12′s.
      http://www.bestracingtips.com/racing-tips/perfecting-the-mustang-5-0-launch-part-2/

      • Billy says:

        Thanks alot. I forgot to mention I have adjustable lower control arms and a aluminum driveshaft also. My goal is the 12′s on motor I Just have to get to a track to see what it will do. I’m not sure how much difference a track makes but it doesn’t hook at all on thr street.I also have a 100 shot on it but I’ve never had a chance to use it. Do you think it’s possible to break into the 11′s on the nitrous.

        • Tommy says:

          11′s are definitely possible. You just need to work on getting your car to hook up. Traction on the starting line can be better or worse depending on your local track conditions. You need to make sure you heat up your tires enough. If you don’t already have one a line-loc helps out a bunch. This way you can hold the car still while you burnout. With your 4.10 and drag radials you should be able to pull a 1.8 in the 60′ time. You’ll probably end up finishing in 4th gear in the quarter mile. There’s too much of a ratio drop if you shift into 5th and end up going slower. Moving the battery to the rear helps, as will racing springs, shocks, struts, at this point you want to put the power you have to the ground before you look for more power. Most people do it the other way around, and spend all their money on the motor. Then they end up leaving 2 big black marks downtrack and get beat by a car with less hp.

  41. jay says:

    Im building an 86 mustang, im working on gettin in the 10s. Im running a 302 w a top loader 4 speed. The engine and trans are from 69, the engine acording to an engine builder friend is 450 -500 hp, every one doubts that i can make it go 10 but i believe i can. Any advice or input would be great

    • Tommy says:

      Tell me more about your car/motor combination. What mods have already been made to it. I can help you, but I need to know what your baseline is currently. 10′s are definitely possible, it depends on your budget/ combo of go fast parts.
      Tommy

  42. m. wilfong says:

    My son and I built a 1971 Maverick, 306,Trick Flow 205 alum. heads, solid lifter non-roller cam, single 4 barrel, C4, 4.10 gears and 9 X 29 ET drag slicks in our garage, and it ran 12.20′s. That was in 2001, so we know it can be done. Have fun!!!!!!!!!!

    • Tommy says:

      I might have used a slightly smaller head than the Trick Flow 205′s on a 306. The 185′s are plenty for that size motor, but this way you can add that 347 stroker kit later and still have plenty of airflow.

  43. vince says:

    im getting ready to buy a 1989 5.0 whats the stock gear ratio its got the T-5

    • Tommy says:

      The 5 speed ’89 Mustang comes with a 3.08 rear gear, while the AOD automatic cars come with the pathetic 2.73 ratio. For a street car a change to a 3.55 is a good compromise ratio. For street/strip cars a 3.73 is a good choice. For more serious drag strip use with taller than stock 27″ or 28″ tires a 4.10, 4.30, or 4.56 is available.

      • vince says:

        Whats an estimate of the most HP a 302 can put out?

        • Tommy says:

          Vince,
          I need more info to answer your question properly. But I’ll take a stab at it anyway. If you mean a stock block 302/5.0 cubic inch motor, then I would say 500 hp has traditionally been ABOUT the level where the block becomes unglued. Now I know there will be somebody who made more power than that. But he’s on borrowed time for sure. At that hp level the slightest hint of detonation and KAPOW, end of story. The stock blocks wimpy 7/16″ head bolts and 2 bolt main caps and weak block webbing were all designed to withstand much less hp from the factory. Any one of these areas can fail on you at this level of power. If you want to upgrade to a stronger 4-bolt main block IE, A4, R302, Dart blocks, then the skys the limit. Depending only on how much nitrous/boost you put to it.

          • vince says:

            well once my cousin gets back in town ill ask all that its got, but i do know its bored .40 over and it has all after market parts in the motor and has a racing clutch but thats all i know so far.

  44. mitch says:

    Like the pic of the car. How about some more info on it?

    • Tommy says:

      I’ve been meaning to write a post about the red car, but I’ve been extremely busy for quite a while. I’ll get on it in the next few days. Glad you like it Mitch.

  45. Bryan says:

    very interesting site. I am hoping when my car is done I can dip in to the 10′s.

  46. Tommy says:

    Seems to me you answered your own question right in this comment. Like most new to drag racing you spent all your money on making power and none on putting it to the ground (chassis/tires). Your car has plenty of power to run LOW 12′s, 107 mph indicates that to me. Your problem lies in the abysmal 2.1 second 60′ time. My ’83 Mustang (red car on my blog) ran well into the 12′s at only 104.14 mph with LESS than 300 HP, granted my car is lighter than your bird. Sticky tires should be your next purchase, getting your car to 60′ better is job one for you. My ’83 ran a best 60′ of 1.68, using 9 x 28 ET Drag slicks and a 4.56 gear finishing the top end in 3rd gear. I assume you end in 3rd also, it was always quicker for me than shifting into 4th gear. There’s no reason why you can’t get your heavier car to run at LEAST a 1.9 or even a 1.8 60′ time. Doing so should put you solidly into the 12′s at which time you should replace the rear upper and lower control arms with some better quality aftermarket pieces to eliminate any wheelhop (Mustang parts are EXACTLY the same).

    What rpm do you launch at? If you have to baby it off the line to eliminate wheelspin, you’re never going to go fast. Of course a WFO start like I used on my ’83 totally destroys the factory clutch after 2-3 passes, so plan on upgrading that too. Or plan for a wrecker to bring you home from the track. Change the tires and the clutch, then let me know if you haven’t made it into the 12′s yet. I’m betting you have. With better tires and clutch you’ll be able to install a much more drag racing friendly gear in the rear like a 4.10.
    Tommy

    • Davy says:

      Great site, noticed you ran a 4.56 gear for the 1/4 and finished out in 3rd, how would that apply for an aod trans, with a 3400 stall?

      • Tommy says:

        It should work out fine for your car as long as you use the 28″ tire. The SROD 4 speed in my car has a 3rd gear ratio of 1.1:1 and a 4th gear of .70:1. This compares favorably with the AOD tranny which has a direct drive 1:1 3rd gear and a .67:1 4th gear. Your car, like mine will be quicker and faster finishing in 3rd rather than 4th because of the huge ratio/RPM drop on the 4th gear shift. The car is much more capable of absorbing such a drop on the 1st to 2nd shift, because the car is moving much slower than it is on the 3rd,-4th shift and wind and rolling resistance is much less at the slower speed.



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