I'm was talking about the head cfm rule of thumb 2 hp per cfm. The magnum head is supposed to flow around 205 cfm.
You don't see too many street cam and cr hit that rule even a lot of the engines done on engine masters challenge don't even.
OK, I was thinking carb cfm's.....now it makes sense!
Honestly, for the street, I'd let HP number fall where it will and not focus on that... it's where the torque curve falls in the RPM range that is important for that use. When I see an engine test where the torque numbers start at 3000-3500 RPM and go up, that usually is a clue that general driving-around street performance is not what was in mind in the parts selection.