1/26/2022 09:21:45 PM


Head Flow Ratio Calculator

Back HomeWallace Racing Back to
Calculators ProgramsBACK to Calculators

Superflow determined a long time ago that the maximum ideal value for head flow ratio is 146 cfm/sq.in.
This number is for an 'ideal' frictionless orifice with no dump or expansion losses.
A good ratio would be 133 cfm/sq.in. for a single intake valve.
137 cfm/sq.in. is good for a 2 intake valve setup.
If your flow ratio is smaller than the 133 cfm/sq.in. then you are losing some power.
Talk to your head porter and see if he can get some better numbers.

Head Flow Ratio Calculator

Number of Cylinders:
RPM at HP Peak:
RPM at Torque Peak:
Rod Length:
Head CFM (@ 28"):
Intake CSA:

Input Stroke, Bore, Please

Wallace Racing Pontiac Store