Ok Rob you have my attention. So, on a standard big block, when changing from, lets say 452 head and using a 516 head about how much compression would it increase? Other brands going from open chamber to closed chamber it is a drastic increase in compression. It appears through reading, the change alone nets maybe a 1/2 point or less, then the ports are not as good also, not to mention smaller valves and no hardened seats. So, decking the 516 heads, changing the valves, installing seats, etc would no longer be cost effective, or am I misinformed?