Look for the list number on the main body casting and choke air horn. The number is stamped into the metal in one of these locations.
Write down the set of numbers that begins with a letter. There are two sets of numbers. The number on top is the list number, and the bottom numbers are the carburetor's date code.
Locate the list number in the first column of the Holley Carb Numerical Listing. The mode number of the carburetor is displayed in the second column beside the list number.