Carburetors come in all sorts of different shapes, configurations, and, of course, sizes. Typically, Detroit has used carburetors with cfm ratings much higher than what might be considered correct. For example, Chevrolet used carbs as large as 800 (780) cfm on engines such as the Z/28 302. In other cases, GM regularly used large-cfm Quadrajets on any number of engine combinations, large and small. To be fair, the QJ incorporates small primary bores; but, nonetheless, it was still a "large" carburetor.