Found this article. Maybe useful to some.
5.0 Racing on a Budgetby Joe Munsch ©2001
- How fast can you afford to go? Or better stated, how much money are you willing to spend to get your Mustang, or any other ride, to go fast? its no secret that going fast is expensive, so I determined early on that I wasn't going to spend my retirement savings to go fast. I wanted to have some fun, win some races at the track and beat my Mustang buddies on occasion.
If you have an unlimited budget for making your 5.0 EFI Mustang go fast don't waste your time reading this article. There are plenty of ways to go fast if you have gobs of dough. But if you like the idea of a stock appearing naturally aspirated, EFI Mustang that runs mid elevens every weekend without breakage and on a shoestring budget, maybe you can get an idea or two from my experience.
My theory, from the beginning, has been to spend no money on parts that didn't make me go faster. I've stuck to that plan fairly well for the past few years. My goal was to make my 15-sec. AOD coupe go 12s with as little expense as possible. I began by attacking the fundamentals.
Intake, throttle body, mass air meter, rear axle ratio and torque converter all had to go. I saved my Edlelbrock EFI intake, C&L 73mm MAF, BBK 70mm throttle body, 1-5/8" MAC shorty headers and 2-1/2" FlowMaster mufflers from my previous car. These parts had proven good so they immediately went on this car. The car wouldn't break the street tires loose at the track so I acquired a B&M Holeshot 3000 converter. Wow! What a difference that makes. Those changes got me to the 13s.
Next the heads, cam and gear had to go. I bought the cheapest proven aluminum heads I could find. At the time the Trick Flow twisted wedge heads were the latest thing and sounded like a good risk. Good flow without huge runners and the valve placement that allowed for long duration cams without cutting the pistons was a plus. I eventually shaved the heads to get the chambers down to 58cc. This makes for about 10:1 compression with flat top pistons. I figured the AOD would need all the help it could get from gearing so the stock 3:27 gears were exchanged for a 4:10 ring and pinion. A Blue Racer hydraulic roller cam with .512 lift and duration of about 224 @ .050" was added. This, along with some Mickey Thompson Sportsman tires got me to 12.60s. Later, I invested in some 10" slicks, 90/10 struts for the front, Eibach drag springs, front skinnies and Centerline racing wheels and a 4000 stall converter. These changes along with a cam change (CompCam 282HR, 564 lift 232/240 duration @.050") got me to low 12s at about 110 MPH. My next move was to swap the AOD for a C-4 with a 4500 stall, kick off the mufflers and tailpipes (I begged a set of long tube headers from a buddy) , install a roll bar and sub frame connectors and remove the rear and passenger seats. I also slapped in a Summit, plastic racing seat and RJS harness. That got me to 11.45 at 115 MPH. Keep in mind that all of the above happened over about a five year period.
I am still using stock rear control arms with stock bushings and the factory quad shock setup (I had to reverse the horizontal shock for tire clearance). I changed to 24# injectors when I got to the low 12s. I ran 12.40s for a year before going to the larger 24# injectors. I used the stock in-tank fuel pump while running high 11s. I only went to a larger capacity pump after adding an electric water pump drive. The voltage draw of the water pump motor was lowering battery voltage and caused the stock pump to fall behind at high RPMs. I still use stock Ford ignition and wires although I did add a high output factory style coil just for grins. I was forced to purchase a chip to extend my RPM limiter so I could get to the finish line without bumping the 6250 limit. I use the stock in-dash tach and gauges. The only additional gauge I have is for fuel pressure. My C-4 tranny is stock except for a manual reversed valve body and a HD low/reverse servo cover. Axles are stock Ford units as is the positrac unit.
Some things I've tried that may or may not apply to your application:
- Lift bars I tried two different brands of "lift bars" and neither one improved my 60-ft. times so I removed them and went back to the stock set-up. "Why go back?" you say. Because, the Fox body cars are notorious for weak torque boxes. The area where the lower control arm attaches to the body gets hit hard every time the car launches. So I decided to keep my soft bushings to cushion the blow. It seems to be working since my car has about 3000 launches on the original suspension and is still going, without chassis damage. I have replaced the upper control arm bushings once.
- MSD Box A friend gave me a MSD to try. It didn't lower ET so I removed it. Don't get me wrong, an MSD may be great for high compression motors or nitrous and supercharged applications but for me it wasn't worth the risk. Did I say risk?. I've witnessed several incidences of "box" failure that have cost friends and opponents races. If it doesn't improve my ET or reaction time I don't need it.
- Intake Manifold This one is tricky. There are a lot of EFI manifold choices these days so you have to be cautious. I've used a Edelbrock EFI manifold from the start of my EFI venture. It has always performed well for me but I had to try the EFI "RPM" upper to see if it would help my car on the big end of the track. Well it killed my 60-ft. times by about .05sec. and didn't improve ET so I took it off. But remember I said this was tricky. After I swapped the AOD for a C-4 and raised my stall speed up a couple of hundred RPM, I tried it again. It works great with this combination. I maintained my 60-ft. times and improved ET slightly with the short runner RPM upper. It also raised my trap speed slightly, which helps me keep up with the Chevys at the finish line. Follow the manufactures recommendations and read the magazines for an intake to go with your application but remember the basics, streetcars need long runners, high RPM motors that launch at high RPM can use shorter runners. Some day I'll try a Victor EFI or a box upper just to test the theory.
- Cams Stick to the basics here too. The cam is obviously the heart of the engine and can make or break you. Street cars have to be more conservative but I've always been willing to suffer a little inconvenience for the sake of performance. Camshaft lift in a 5.0 motor may not be as important as duration and other profile ingredients. For most of us with 5-liter engines, .500" to .550" lift is plenty. For serious high revving race motors more lift will probably be needed but most of us don't have heads that can flow enough and don't turn the revs to need more lift than the .500" to .550" range. I don't claim to be an expert here but it seems that matching the cams' duration and with your launch RPM and your red line might be the way to go. My car flashes to about 4500 RPM when I let go of the brake, so I use a cam that performs well above 4500. My cam would be bad for a stick shift street car. A stick shift car that launches at 6000 may be able to go with more duration than me but a car that has to launch at low RPM will need a cam with low duration numbers. Call your favorite cam grinder (CompCams has a good Web site) for a recommendation but be sure that they understand your goal. Cam grinders have always recommend cams that are too mild for my taste, probably because I told them I drove my car to the track and to work.
- Converters I started with a 3000 stall and then 4000, now 4500. This is another tricky one. The 3000-RPM converter was an excellent street unit. I bought a B&M Holeshot 3000 and it worked great for a weekend racer with sticky street tires. My desire to go faster caused me to get TransKing in Galveston, TX. to build me a 4000 RPM unit. My 60 times and ET dropped dramatically when the car didn't blow the tires loose. I was forced to buy slicks. The AOD with a 4000 stall converter worked flawlessly for years, and made trips from Houston to Dallas on several occasions, cruising at 70+ MPH with a 4.10 gear. I moved up to a 4500 stall converter when I switched to the lighter C-4 unit. This seems to be a good choice for my current setup. This C-4 converter is totally different from the AOD unit. The AOD unit would rev to about 2100 RPM with my foot on the brake before it would lock up and spin the tires. The C-4 unit has a similar stall but will foot brake to over 3300 RPM. I'm sure that the C-4 unit would have never made it on those Dallas trips without overheating the tranny. More (RPM) is better at the starting line. Your ET is made or lost at the beginning of the track, so get as much stall as you think you can support at the big end. High stall can eat you up if you are short on power at high RPM, so listen to the converter manufacturer and tell him what you have and what you expect.
- Tires/Wheels Lighter is better. I raced with my Pony rims for a long time, and they are heavy. I picked up .10 sec ET by switching to lighter rims and tires. There are many great street radials to choose from now, but I used MT Sportsman Pros for a long time before buying my first slicks. The sportsman tires were good for 1.80 sec. 60 ft on my car. I've tried Mickey Thompson 26"x 10", 28"x 10" and Hoosier 28" x 9" and 28" x 10". They all work good on a low HP car like mine. I use the Hoosiers because they don't leak air without tubes. Bigger is better to a point here too. Bigger circumference and tread width give more rubber to the ground, but big tires take HP to turn, so use what you need to get the job done. Match tread width to rim width, 10" tires won't work well with 7" rims. I use 8 1/2" rims with 10" tires and it seems to be good enough. If you have tall gears, a shorter tire (rear) may help you. Or if you're like me, you may need more height to keep your trap RPM down since most EFI cars don't make much power over 6000 RPM.
- Timing "Timing is everything", some say. It may not be everything but it can make a big difference in performance at the track and on the street. Naturally aspirated EFI Fords usually respond to as much timing as you can give them. Advance it until it pings under acceleration and them back it off a little. Compression ratio, fuel octane, iron vs. aluminum heads, spark plugs, cam specs and more can make your car different from the next one as far as its timing needs and tolerance for pinging. My car worked best with "base" timing in the 16 to 21 range with the stock computer and a launch RPM that was as low as 2000. If it pings at 16-deg. base you need to find out why. Don't forget that many things effect pre-ignition and detonation. Change to higher octane fuel or a different brand. My car always pinged on Chevron gasoline. A colder plug may eliminate a pinging problem so try one step colder than factory or a different brand. Stickshift cars with tall gears and automatic cars with stock converters will benefit most from improved ignition timing curves. An aftermarket chip can be great for these cars because they experience the full range of RPM as they accelerate through the gears. My car runs best with the base timing set at 35 deg. and the "spout" removed. This only works for cars that don't see RPM below 3500 or so.
- Fuel 93-octane pump gas works fine in my car. I've read that higher octane fuel is more stable (less detonation) but contains less energy. My guess is that you should use the lowest octane fuel that will work in your car. The race fuel at the track costs $4.00/gal. and up so if you don't need it visit your local gas station on the way to the track.
- Shift Points Trial and error may be the way to find where to shift your beast. For most of my EFI career I shifted at 5400 to 5800. With a 4000 or 4500 stall converter this means from launch my engine would go from 4500 to 5500 and back again through gears 1 and 2. Third gear would go to 6000+. The sound of a car running down the track within this narrow RPM range is a bit monotone but if that's where your power is...well that's the best place to be. Check out some dyno charts to determine where engines similar to yours start making power and where it falls off. Try to keep your engine spinning within this range as much as possible for best ETs. Note: With my shorter runner "RPM" intake, I now shift at about 6200 for best results and my trap RPM is somewhere around 6400.
- Short Times Short times are the other ETs on your time slip. You know, like your 60-ft., 330 ft. and so on. How important is your 60-ft. time? Think about this. Are you pushed back in your seat more at 60ft. or at 1000 ft.? I'm talking about rate of acceleration and G-force stuff. Your rate of acceleration is much greater at the beginning of the track than at the end so any lack of power or slip of the tire or misfire will be more noticeable by "seat of the pants feel" and on your final ET. So, this is where ET is made. If you screw up at the startline your ET slip will not forgive you. You can tap the brake or turn the key off or forget to shift at the big end of the track and it will be virtually unnoticed on your ET slip. Here's my point. If you are looking to improve you ET then work on the front end of the track. Choose cam, intake, gearing, tires, clutch or converter to get you to the 60-ft. mark as soon as possible. I read somewhere that if you're not prepared to launch at 4500 or higher you should stay home. (Do what you can, there's a place for all of us at the track.) If your engine is only making 60 ft./lbs @ 2000 RPM then don't go there! Get to a RPM where you've got some torque and don't let it fall below that point. This may mean high numerical gearing and high RPM launches. The last place you want your car to be short on power is the first few feet of the track.
- Weight I'm currently on a rampage, seeking to find and eliminate unneeded heavy things. Weight is your ETs enemy. My car is all steel with factory glass and electric windows but I have, over the years, slowly but surely removed some excess weight. I don't recommend eliminating the things that you enjoy but remember that 100 lbs. equals .10-sec.. I've not weighed my car in a long time because my home track doesn't have a scale, but it's fairly light. I've experienced the results of unloading the heavy AOD tranny as well as the rear bumper, passenger seat, some sound deadener under the carpet and rear seat, the console, the radio as well as [since my car no longer sees any street use] the AC compressor, heater core and blower assembly. So I can tell that light weight is good...but don't mess up your street car by taking off stuff you might want back on later or that will ruin you cars re-sale value if you don't intend to be buried in it (like me).