Aluminum or Iron? Dart II, Iron Eagle, Edelbrock, World, Trick Flow, etc., stock? If stock GM, which ones? It's a '73 and they didn't have hardened valve seats so they'll need to cut/install all them at least, one valve is totally toast and I think a couple more aren't doing so hot; guides have 28 years and 280K miles, etc. I think replacement might be better than rebuild in this case? Right now it has 10:1, and an Isky 292/505 cam; Edelbrock Performer with Q-jet, headers and 54" long 2-3/4" glasspacks. Power estimates? What can I expect to get out of this beast with good heads?