Find the perfect carb size for your street or race engine.
e.g., 302, 350, 454
Redline where power peaks
Selecting the correct carburetor airflow rating (CFM) is critical for optimal engine performance. The goal is to provide enough air for maximum power without sacrificing low-speed throttle response.
Many enthusiasts make the mistake of buying too large a carburetor. A carb that is too big reduces the air velocity through the venturis, which weakens the vacuum signal needed to pull fuel into the airstream. This results in "bogging" when you step on the gas.
The standard industry formula used to calculate CFM requirements for a four-stroke engine is:
CFM = (CID × RPM × VE) / 3456CFM stands for Cubic Feet per Minute. It measures the volume of air a carburetor can flow.
A carburetor that is too large (over-carbureting) causes poor throttle response, low-end bogging, and difficulty tuning, as air velocity through the venturis drops too low.
VE is ratio of the actual volume of air drawn into the cylinder to the theoretical maximum volume. Stock engines are 75-80%, street performance 85-90%, and race engines 100%+.
Find the right tool for your next calculation
Calculate engine size (CC/Liters)
Convert torque to horsepower
Find optimal carburetor size
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Check fitment & clearance