I'b building a 455 for my 67 Firebird. I have 2 different sets of heads.

The first set is a #62 from a 69 Grand Prix. They have screw-in type studs, have 2.11/1.77 valves but have a tiny combustion chamber. To use these I will have to buy dished pistons. They are supposed to be 72cc.

The 2nd set is 6X-4 from a 75 Firebird. They have screw-in type studs, have 2.11/1.66 valves and have NOT been to the machine shop. To use these I would have them machined to accept larger valves and I could go with flat top pistons (94 cc) or domed pistons (101cc).

My question is which would be less expensive? Dished pistons or machine work on the 6X heads?

I have toyed with the idea of selling them both and getting aluminum heads but I just don't have the budget for that.