[Racer_X]

Z-linkCobra: A 302 at .030 oversize pistons is a 306c.i.

ZoaFan08 - I'll also echo using the AFR 185 heads with 65 c.c. combustion chambers.
You don't want a lot of compression with blown or turbo engines, especially small block fords, as they have a tendency to lift the heads with anything over 7-8 psi. Run ARP studs, Cometic gaskets (o-ring preferred) and a flat top forged piston or even a dished. Drop that compression down to a more blower friendly 8.0 to 1 or lower.

Folks have been known to get plenty of HP with the stock H.O. cam. Remember, it's all about effeciency of getting the fuel/air charge into and out of the combustion chamber. ARP Rod bolts are a MUST as the factory rod bolts are a major weak link on a factory 5.0 engine. I'd suggest H-beam rods with ARP hardware, ARP main studs, and a windage tray. If you're looking at 500HP, you're going to split that factory block down the middle of the crank and cam bore. They can't take 500HP and live a long time.