Understood but..the air velocity is number one and the cams job is to control the velocity of the air through the port. The ability of a specific engine combination to use what the port is capable of is probably why some engines make more power than others with the same head. Using the port length and CC's you can calculate the average size of the port. Then using the bore and piston speed you can calculate the air velocity at each degree then in turn calculate the average port velocity that the engine is creating or demanding through a given port. If that number is too low or too high then power will be less than optimum.