Calculate CFM from actual vacuum reading of carb



Want to see what your carburetor is flowing at wide open throttle at your maximum RPM?

Use this calculator to find out what the carburetor is flowing by finding out what the vacuum reading of the intake is at full throttle at maximum RPM.
(Or could use to see what it is at any RPM range?)

Usually for best HP, a carburetor should have 1.5" Hg at full throttle at your maximum RPM.
(for a 4 barrel carburetor, 2 bbl were usually tested at 3" Hg)


Calculate Carb CFM From Vacuum
Enter Carb CFM:
(from Manufacturer Rating)
Enter Vacuum Carb Rated At:
(from Manufacturer)
Inches/Hg
Enter Engine Vacuum Measured:
(Usually at WOT)
Inches/Hg
Input All Data, Please
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