This is all good stuff. Forgive that I don't keep tabs on the combo but offer suggestions. In my mind, the parts combo I thought you had were doing well making 575 with the small cam. In retrospect a high compression, ported aftermarket head 4xx" with a cam better than a flat tappet should make more so, it's doing good! Did you have the intake ported? I think it's still using a 4150 carb?
