Dissecting the Rochester

Your guide to the most popular Rochester Carburetors 2-Barrel The Rochester 2G carburetor was introduced in 1955, and was used in various applications by all GM divisions through 1979. It is easily identifiable by the words “2 Jet” on the air horn (lid). This carburetor was made in two base sizes. The original “early” size has center to center stud dimensions of 2” x 3-¼”, and a bore size of 1-7/16”. The larger base stud dimensions are 2” x 3-¾”, with a bore size of 1-11/16”. In all, 5 cfm (cubic feet per minute) sizes were produced, ranging from 278