I think what your previous post and the caluclator shows is there are ALOT of different formulas for the rpm range based on CSAs, choke points, cc of port, cc of entire intake tract, etc etc. They ALL are just ball park estimates and real world combinations have alot more factors in them.
It is the reason why 3 different heads from the same manufacturer, same port length, same cc, probably the same CSA, same intake, cam,carb can have 3 different rpm ranges! SHAPE!
|