12/4/2023 07:59:18 AM
Head Flow Ratio Calculator
BACK 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.