Restocreations What is needed is more info on the motor and what you are looking for in power, drivibility, cruising, easy maintainance, and Idle lope for noise. What is the owner looking for???
I started with a 452 motor, I build only torque motors. This is what moves the car from a stop, not HP at 6,000 rpm. Raced the same motor for 8 years and now running a 482 for 6 years. My 482 motor has a crane hydro roller 587/607" in it. I have a stage 2 head job done on Shelby heads. Stroker kit came from Barry R. Maintainance is not much. Motor at the flywheel is 620ft torque and 525HP at 5,900 rpms. Ilde is a little lope. I run a single plane FI system for the 15 years and have been very happy with motor and setup.
The camshaft you are talking about is small BUT here's the thing, Does this driver have alot of time behind the wheel of 500HP??? how about 600HP?? Having the biggest motor in a cobra is not always the smartest thing. YOur owner might be happier with a 482 motor. 4.25 stroke and bore. Max safe rpms 6,500. This will give a long life to this motor. Is the owner looking to smoke the tires for 300 ft off idle?? Another thing is are we running hydro rollers or solid rollers?? Either way we are going to need valve springs up to the ability to hand and control the valve train. I can tell you that running a hydro roller lifter will cost you about 400 rpms in motor because of float with the same valve springs. Matching parts is going to be very IMPORTANT. HYdro lifters pump up at about 6,400 rpms and float the valve train. Mr. valve smacking Mr. piston is not going to be pretty without a rev limiter. I run mine to 6,200 max. I get a float at 5,800 rpms but the motor pushes through because of setup of the rockers. I also run a beehive spring. 12 years no problems. BBC work pretty good for 5,500 rpm motors. If you are looking for more RPM PAC valve springs have a higher spring rate in the 420 range. These will get your motor to 6,500 rpms.
How much head work is done to these heads??? KC stage 3 heads with max flow?? IMO I wouldn't run anything bigger than a .630/.650" with 112 LSA camshaft in a 527 for the street. This will give you good power in a wide power band. Not spin the motor over 6,200 rpms and give you many years of life. This is a hydro lifter camshaft. Solid lifter would be in the .650/670" with a 110-112 LSA. 6,500 rpm max. I know guys running .700" lift cams and bigger. Problems are replacement of valve springs every couple of years, hard wear and tear of lifter wheels on camshaft. FE lifter have a small size. If going to high lift camshaft have the block lifters bored to .904" dodge BB lifters. Wider wheel and handle load better than .875".
The spec left out are about the motor, Carb size, intake manifold design, header pipe size, what kind of side pipes are you running,(street or race) rearend ratio and trans ratios. IMO and I am running a 3.31 gear in the rearend, and thing high will make the car hard to drive from stand still. It's hard to get cobras to hookup and run. What clutch are you looking at?? I think the numbers above will be the best for a 527 motor and give endurance ability and fun to owner. Going bigger on camshaft will give more power and shorten life of motor valvesprings and beat valve seat up faster. I am building a 498 motor with 11.0 compression. Camshaft is in the .630's with a 112 LSA. Looking at 650HP at the flywheel and almost 700 ft of torque. This is past the safe limit of a cobra. I drive the car hard and abuse it on the track to a degree but have only had 2 broken rocker shafts and killed 1 clutch. This is with street tires, 17". More important thing is
oil pressure, limiters to the heads, oiling through the pushrods. 30 psi at idle and 65-80 psi at 2,500 rpms. This motor like
oil pressure even with BBC rods and scat crank shaft. I am running shelby blocks that are center oilers. Rick L. Ps over 30+ years of racing I have learned that bigger is not always better unless winning is the only thing and you have DEEP POCKETS.