"Saw your second reply!!!! I bet, they get proud of their stuff when you get into one off pieces!!!! The last full on race motor I had was a 447 (0.100 over 427) and it was 15 1/2 to one, closed chambered heads with a set of open chamber style piston hand fitted to the combustion chamber, took the machinist and engine builder that did all the machine, head and balance work close to forty hours of grinding, claying and checking to get them that close of a fit, and bet yours is like it, it exploded when you initially fired it, actually had people jump off the ground in the staging lanes if they happened to be close to it when I would start it because it startled them so bad!!!! And although a big block most that had not seen the hood off would swear that was the nastiest sounding small block they had ever heard because of how quick it revved and turned up when it left the line!!! Hope it last for a long time with no issues and stay safe and have much success!!!