Originally Posted by machine shop tom
Along with the loss of compression from going from a 60ish cc chamber to 64ccs, you have also lost perhaps a point of effective compression because you went from a cast iron head to aluminum head. If you want to stick with flat-tops, you would be better served with a cast-iron head, perhaps an EngineQuest Vor-Tec head with the manifold mating surface that matches your existing intake manifold.
Not to hijack the thread but I just used a set of those on an inboard boat engine. I have to say I was pretty impressed with them. The quality of the castings was up there and even the valve job could have been used right out of the box. For my customer it was a win win because he was able to retain his cast iron intake and get the benefit of a vortec style chamber. The price was also a steal at $280 each bare.