WOW..... That is awesome. I was thinking 450ish. I have a set of Ported X heads I would like to use on something, thinking they are not enough for my soon to be 416. As we already talked about my goal is 500/500 or a tad better. The X heads flow 250 @ .550 Not outrageous but they were done for a 340 build. May just sell the X heads to help pay for aluminum heads. They were virgin low millage 69 X heads, new hardened seats, stainless Milodon valves, 5 angle valve job, valves back cut, new Comp springs max lift .550 130# seat pressure, gasket matched and bowl work.