383 piston choice

I just put one together with a stock style, (no valve relief) piston set. At .020" in the hole, and using a .039 gasket, I still would not have room for that .484" cam you wish to run. The 75 CC heads I have did keep my compression up to just under 10:1. If you are looking at trying for 400+ HP, I would choose the RPM intake over the Weiand. Good luck.