all i can say about the "P" heads is that they are roughly 58cc, outflow the GT40 heads and have better combustion chamber design. The drawback is you have to use special headers and that could be a pain. I just bought mine and i am going to put mine on soon. If your staying NA, shave them if you are running stock pistons(depends on what you have though). I will be shaving mine .030" and running an E cam hopefully. This is all trial and error for me.
James
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Cobra brakes are on! Finally.....
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