Ive got a 340 build going on in the small block forum. I ccd the performer RPM heads and every single cylinder was identical. No variations. The heads ........now that I think of it had port work done to them, I dont know by whom, maybe they did chamber work as well but I didnt see any signs.
Cant open the links till I get home cause my internet is too slow at the shop but Ill check them out
