"I've got a really good set of aluminum Dart II heads here in the shop--I'll probably try them, too. But, I've got to believe that the iron heads will keep more heat in the chamber and make more power. Those Darts flow like crazy, though. I'll try them both with the cams I've got in mind, and whichever works best is what I'll send in. I'm thinking it'll be the Pro Action parts."