So I have a friend trying to sell me some 69 351W D00E casting (?) heads. He seems to think they'll bolt on to my stock short block and says they're worth a good 40 - 50HP due to smaller combustion chambers. I don't think he's BSing me but before I think about buying (appaerntly I'm getting a good price) I was just curious if anyone here had any opinons about them or anything?