Flow is not how you should pick a cylinder head. You need to know what you want from the engine, and then get the head csa where it should be. If you have a 2 heads, one flows 280 cfm at .500 and the other flows 300cfm at .500, Most times the higher flowing head will have a larger port/valve. If that's what the engine wants (HP, RPM) then it will make great power. If not, it will be a bag of $hit!
Brian
