* Engine modifications: A stock 350 will need a much smaller carburetor than a heavily modified one with high-lift cam, ported heads, and high compression.
* Intended use: A street-driven car will have different needs than a race car. A street car might tolerate a slightly smaller carb for better drivability at lower RPMs.
* Engine RPM range: A carburetor needs to supply enough fuel across the entire RPM range the engine will operate in. A carb too small will starve the engine at high RPM, while one too large can lead to poor low-end performance and drivability.
General Guidelines:
* Stock or mildly modified 350: A 600-650 CFM carburetor is often a good starting point.
* Moderately modified 350: A 700-750 CFM carburetor might be appropriate.
* Heavily modified 350: You could need 800 CFM or more.
It's crucial to understand that these are just rough estimates. The best way to determine the optimal CFM is through careful consideration of your engine's specifications and intended use, potentially with dyno testing for precision. Choosing a carburetor that's too large will result in poor fuel economy and drivability, especially at low RPMs. One that's too small will restrict airflow and limit horsepower.
