I used 93% efficiency to suggest a typical moderate build. At 100% it slides up to 116 cfm per runner. As a whole, the math says 936 cfm for a 541 at 100%. Then, you get into real world restrictions, carb sizing bumps, and such.
I think you are assuming that all eight cylinders have the intake valve open at the same time. If #1 cylinder is just opening the intake valve, and we have a 300 degree duration cam at .006" lift, then we have #2 still open (90 degrees past opening), #7 still opening (180 degrees), #5 closing at 270 degrees past opening, and #6 is already closed assuming the standard firing order. So only two cylinders are flowing a lot of air. I think Darin Morgan said we have about 2-1/2 cylinders open at any time. 936cfm (total)/2.5 cylinders=374cfm per cylinder.
Correct me if I'm thinking this the wrong way.
