340x vs. Edelbrock aluminum heads.

Jim T, I'd look for power elsewhere besides the heads. A 340 cammed engine in a 4spd is a nice set up. More power after bowl porting X heads is in the cam and intake and exhaust.
Depending on how you want to have it look, stock or not can help dictate what you do. F.A.S.T. cars have a great stealth look and secret cams. Run like hell.