I'm at the point where I'm ready to place my order. After all my research, running Desktop Dyno, and reading Andy's book, I'm leaning towards the complete 440Source 512 kit. I was going to go with the 528 but the 512 seems to make more power no matter what I throw at it. This is the RB version of course. The 499 would be my next choice. Either one is using a .055 overbore.