280CFM on what i assume were hand ported heads is pretty impressive actually. But I suspect that is the max limit for hand ported. Like someone mentinoed, Hughes cnc and wide mouth cnc can do huge numbers, 300+cfm starting at .500. If he put heads with that kind flow and a bigger carb. Yeah, that's a recipe for 600+ horse in my mind. Maybe even 650+ if the work is done right.
