Carburetor CFM Calculator

Your details

Choose the unit your engine displacement is expressed in.
Total swept volume of all cylinders. Common V8 values: 302, 350, 383, 396, 427, 454 CID.
in³
Presets a typical volumetric efficiency value. Choose "Custom" to enter your own.
The highest RPM the engine will regularly see - typically redline for race engines or peak power RPM for street builds.
RPM
Race-specification carburetors deliver better fuel atomisation so a slightly larger CFM rating is acceptable without drivability loss.
Required CFMSmall-block street
445.6CFM

Minimum carburetor airflow rating for this engine and RPM

Recommended carb size450CFM
Displacement used350in³
VE applied80%
CFM per cylinder (V8 est.)55.7CFM
445.6 CFM
Small-block street<450Performance street450-650Street-strip650-850Full race850+

Recommended carburetor: 450 CFM

  • Your engine needs at least 445.6 CFM at 5,500 RPM with 80% VE.
  • A 450 CFM carburetor is the closest standard size at or above the calculated requirement - a well-matched choice for this build.

Next stepPair your carb choice with a matching intake manifold and camshaft profile - a large carb on a stock intake will not deliver its rated airflow.

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