Producing over 250,000,000 carburetors since becoming established in 1903, Holley Motor Company is named for founding brothers Earl and George Holley. Each carburetor produced is rated for cubic feet per minute (CFM), a measure of air flow. Holley's "Carburetor Numerical Listing" provides brief specifications by model number, including CFM rating.
Read the list number off the carburetor. The list number is located on the choke air horn, above the date code. On 4500 models, the list number is located on the top of the main body.
Download the Carburetor Numerical Listing from the technical library on Holley's website (see Resource).
Find the correct list number on the numerical listing, and look in the third column to find the CFM rating.
