I was recentlly offered a 'ported and polished' B20 head. I have one on a engine I have and it's great. But I don't know enough about them to buy one off an engine for the kind of money that was being asked.

Is there a standard flow rate criteria for testing a head? Like is it always that X psi (or inches of water) will give you Y CFM in a stock b20 head and that a 'stage I' head will give you 10% more and a stage II head will give you 20% more? I would assume that both intake and exhaust are openned up. Do you want to keep the flow rate ratios the same?

Thanks for any insights on this.


Chris