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Yo Ken! - Tech Q & A - October 2013
Answering your technical questions
I’ve read a lot of your online articles and have purchased several copies of the magazine. It seems pretty clear you know more than the people I have already talked to about my dilemma.
I have a ’96 GT with 120,000 miles, and I want to know what I can really expect by replacing stock heads and cams with the Trick Flow Twisted Wedge top-end kit and Comp Cams that you are always mentioning. A website selling the top-end kit claims that a TFS top-end kit along with a tune will take 215 hp to approximately 320. Is this fact or fiction? Others have recommended a Procharger or crate motor. I’m interested in achieving 350-400 hp to maintain driveability with performance without breaking the bank. Do you have any advice or suggestions?
Tim, you will be looking at 300-320 hp, depending on your tune. You cannot reach 350-400hp with a supercharger alone. The heads on the ’96 4.6 cannot support the airflow needed to achieve your goals. Unless you plan to run very aggressive cams, getting to 350 will be a stretch and you will lose driveability.
Go for the top-end kit from TFS and add the supercharger when the budget allows. You will see the better part of 450 hp with the TFS and supercharger.
I’m building a 347 stroker, it has a 28-ounce flywheel from a 351 Windsor. My bellhousing will not fit over flywheel. What bellhousing combo do I need to mate this motor to my T-5 transmission?
South Pekin, IL
Jeremy, the correct flywheel is a 28-ounce 157-tooth flywheel to be used with your T-5 trans and bellhousing. You most likely have the 164-tooth flywheel, which is obviously too big.
I have to tell you guys that you have the best Mustang and Ford magazine out today. There are many others that try but can’t contend with MM&FF. So on to my burning questions.
I have an ’07 GT/CS with many mods, and I’ve run into a few minor problems along the way. The car has BBK long-tube headers, high-flow cats, custom Spintech mufflers, Typhoon intake, underdrive pulleys, Predator with a custom tune, BBK throttle body, custom-ground cams, a Zex 75-to-175-shot wet nitrous kit, and full-length subframe connectors. It also has an aluminum one-piece driveshaft, a Steeda Tri-Ax shifter, and an SLP line-lock. I’m making 368 hp on the dyno and 420 on a 75-shot.
Now onto the problems.
My shifter rattles when I first start the car, and I have no clue why.
When I accelerate over 70 mph and let off the gas, the driveshaft starts vibrating really bad—why is that?
Sometimes my rpm gets stuck at 2,000 (or higher) ever since I changed the throttle body. Do BBK’s have a problem with sticking? If so, how do I fix it?
I have 16x8 stock rims on the back with 9-inch slicks. Can I put 10-inch slicks on those wheels, or larger? They just won’t hold at the track.
Can I safely run a 100-shot on the car without blowing the motor? My mechanic says no, but all my buddies say yes.
Any advice or answers you guys can give would be awesome.
Via the Internet
Rich, when it comes to the shifter rattling, you need to check all the fasteners. Also remember that aftermarket shifters do not use the same type of isolation bushing as the factory. A factory shifter is designed for the masses, a combination of comfort and performance.
The driveshaft vibration could be one of two things. The most obvious is it’s out of balance or bent, or it could have bad universal joints.
The throttle issue is most likely in the tune. Since you have a drive-by-wire throttle, a problem of the throttle body sticking is highly unlikely.
A 10-inch slick will work on an 8-inch rim, but it may not help. If you cannot hook 420 hp on a 9-inch slick, then you have to improve weight transfer and suspension.
A 100-shot of nitrous is fine as long as the manufacturer’s recommendation is followed. It’s not too much for your 4.6 to handle.
I have a question regarding the rear coolant crossover of a small-block Ford engine. I have a 331 in my ’92 Mustang that is 8 years old. The engine has many street miles on it, along with dragstrip passes. I did a compression check and found that cylinders 4 and 8 had 60 to 70-psi less compression than the other six cylinders.
When disassembling the engine, I noticed that my intake had no crossover passage. I understand why the EFI intakes do not have one, but would it be beneficial to add an external crossover? I did check—the rear of the engine didn’t run any hotter as far as peak temperature is concerned, but when the rear of the engine got hot, 190-200 degrees, it didn’t cool off like the front of the engine, which would fluctuate from 180 to 190 degrees. Could this have caused the rear cylinders to wear faster?
Brian, loss of cylinder pressure in your engine is not due to coolant flow. The most likely cause is normal wear accelerated by racing. Ten degrees in front-to-rear cooling temperature is normal. These engines have been engineered to handle high heat loads. Cooling is not an issue as long as the cooling system has not been compromised.