That's the maximum CFM for a Quadrajet, but it's got a spring-loaded air valve over the secondary throttle bores which effectively prevents over-carbureting the engine. It physically cannot flow too much air, and the secondary air valve is spring-adjustable to control the rate of opening. Look at a Q-jet sometime- - - -the primary barrels are tiny, and there's a 3-stack venturi in each primary bore that has a progressive approach to fuel metering. The only time the secondary barrels get into the act is when the primaries can no longer supply the engine with enough air volume, and then the fuel metering is tailored to the airflow.
In short, a properly calibrated Q-Jet is virtually idiot-proof, and there's a smooth progression from idle to full throttle RPM with no flat spots. I started going to Rochester training schools in 1966 when the Quadrajet was a brand new design. I've rebuilt several hundred of them, and taught hundreds of students to repair carburetors in my 30-something years as an automotive instructor. In my decidedly biased opinion, the Q-Jet is one of the best-engineered carburetors out there, whether it's used on a stock street engine or a hotrod. One 460 cubic inch MOPAR tractor pull engine I built made 714 HP on the dyno with a single Quadrajet and Cam 2 racing gasoline.
Jerry
