Rochester Quadrajet's

Generally Speaking

The Rochester 4MV Spreadbore {Advertised at; 750 CFM} was the same Carburetor
utilized on most of the Chevrolet > 327, 350, 396, 402, 427 and 454 Engines
from 1966 thru 1973.

The only difference was in the Main Jet, Main Rod, Secondary Rod, and Needle and Seat components.

Most of the Spreadbore's mounted on the 350 Engines had;
* Main Jets ......... .067"
* Primary Rods ... .038" or .042"

Most of the Spreadbore's on the Big-Block Engines had;
* Main Jets ......... .071"
* Primary Rods .... .044" or .046"