REFLECTOR: Intake sizing

[Ron N VelocityXLFG]

Is there a known formula for sizing your intake.
I took displacement*(rpm/2) to find how much air the engine needed.
Then I came up with a speed to optimize to and calculated the amount
of air I was passing through to come up with a Intake surface area to use.
I know it is very rough calculation. Is there a well known calculator 
for intake sizing?

Ron