[Excaliber]

You know I forgot to consider the fact you haven't yet selected the cam. Sounds like you have a very nice strong motor capable of high rpm. I always match the CAM to the SPRINGS by buying a 'cam kit'. It's possible you could get to big a cam, go for the high rpm and find the single spring is not compatible with the setup. Whatever heads you get if they flow LESS than the cam will allow for then theres your 'bottle neck'. There is always a 'bottle neck' somewhere (headers, carb, valve size, cam profile, etc.). The key is matching the components to the end result you seek. Such as 'cruise rpm'. If the cam profile works best at 3000 and higher and you 'cruise' at 2600-2800 rpm the motor will not be working within design parameters. Maybe you don't care about 'street' use. So you get a cam that runs to 7000 and the heads limit performance at 6200, theres your bottle neck! Or the valves 'float' (single spring) at 6200 and the heads and cam are good to 7000.

Match the cam and springs to whatever head you decide to go with. Don't forget to at least consider 'cruise rpm' (cam profile and rear gear ratio) and how that impacts streetability with your setup. I rebuilt my motor for the street, when I got the car it was setup for high rpm drag race duty. REALLY unpleasant on the street! After rebuilding (more modest cam, reduced compression ratio, smaller vacuum secondary carbs) performance was BARELY down from what it was, gas mileage was DOUBLED and streetability was dramatically improved. I love to race but fact is, 90% of my driving was on the 'street'. Just say "NO" to radical race profiles unless your a serious racer! I STILL run in the 11's and gave up an estimated 150 horse power when I rebuilt for the street. Think about that, clearly my Cobra was 'traction limited' not horse power limited! If you can only hookup 500 horse, 600 IS truly a waste of time.