I guess the "thin casting" part is why most seem to be on 655's then. Need the cubes to make up for the inadequate head. I am just musing and wondering. I know about Mike Sanders/Clintons deal. For what I understand there were only two sets of heads out there but I could be wrong there. Talked to Mike about his at an NMCA race some. I know of some of this stuff out there for sale but my experience with them is somewhat limited to helping a Canadian buddy who has a 655 with these heads. FWIW my junker is faster than his deal even though he has 50 cubes on me. Just curious what the potential might be.