zrayr Z this will turn into a questionable answer. From my own personal 14 years of owning a cobra and abuse at the track 95% of the time, here is what I have found. Matching parts for an rpm range is most important. If the power range is between 2,000 rpms and 5,800 rpms you build a motor for this range with parts. Intake manifold, compression, exhaust system and most important, CAMSHAFT design and valve springs. I built a shelby block and head motor with a 9.2 compression, 501/533" hydro camshaft and stock ERA exhaust. Car made 368 HP and 420 ft of torque at the rear wheels. This was with a stroker crankshaft from a stock 428 motor. 3.98" The cylinders are bore of 4.25". I build torque motors, this is was moves the cars, HP is for topend speed. I also believe in a peroiler system for the motor. Car will pull just under 1 "G" on a skid pad. I have learned that anything over 500 rpms past max hp numbers is all you need to spin the motor up to. ANY THING more than tis is just wasting motor life. Maintainance of checking bearings each sprring and looking for any damage or metal flakes in the
oil pan are important to longer life of the motor. If you are running an FE bottom end, which I was, I run high
oil pressure when racing. Between 65-80 psi hot on the track. I ran this motor for 8 years and have no failures. I run a 15w-40
oil and Lucas oil suppliment and small bottle of EOS. 75% of the wear to a motor is on startup after the motor has been sitting for a week. prelube with giving the motor a 35 psi pressure before starting saves alot of wear and tear. I have only $14K in this motor. The motor now with the same block and heads is a 482 motor. Same principles apply to this motor. I have gone to a hydro roller camshaft with a .586-.607". I have also gone to beehive springs that have less weight than the stock valvesprings and top caps. The couple of oz's has increased the rpm range 300 rpm more and raised the valve float to 5,800 rpm, the motor just pushes through this spot. Max rpm is 6,200.
Here's the thing, if you want to build an FE motor, stroker it with a 4.25 crank and chevy rods. This will make it just about bullet proof. I would still not rev this over 6,500 rpms. HVHP oil pump with an #80 pound spring. This will work good for street and a little track fun. Having ports on the intake and heads will make 10-30 hp more that stock. The exhaust is the big choker of the power. If noise is not an issue, go for loud pipes, low back pressure, and ear plugs. forget about talking and driving. Watch out for the cops with DB meters in town after dusk. You can also buy 2 sets of pipes, one for track and one for street. Run a lite flywheel on the car 20-22 lb one,not the 40 pounds that comes stock on most motors. Rearend ratios and trans ratio need to work togeather to get the most power to the ground. Barry R. has a book out about max hp from an FE motor. BUY IT and read. Jay Brown is also coming out with a book in a couple of weeks with more info on each part and which ones work better than others. You can build a nice 445-482 make great power, run on hightest gas 91 0ctane. Smoke the rear tires in 3 gears. Make about 600ft, of torque and 540hp. This is what my 482 makes. idles at 750 rpm with a little lope sound. running for 5 years now and no problems. I did have 2 failures of rocker shafts and have fix this with running ersons now. limit to 6,000 rpms, motor will last for many years with basic service. Have to remembeer the car ownly weights about 2,500 pounds. TOO much power is as bad as not enough, only different is one makes you look silly the other one could get you kill.
Rick L.
It's about the clearances, rpm limit, and oil pressure
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