Everyone talks about CFM numbers when there heads are flowed. I think we all agree that different benches and different ways of testing will result in different end numbers. Well I have some questions.

What are the typical gains we see in CFM flow % between the different porters?

What is considered a good % increase in flow? (Stage 1/2/3 and Stock valves vrs Non Stock Valves)


I also understand that you can hog out a port and get a large % increase in flow but loose velocity.

How do you test for that?


Well I think that sums up my questions for now. Thanks in advance.