The Rochester Quadrajet was the factory carburetor on most General Motors performance cars from the mid-1960s through the 1980s. It has a terrible reputation that it only partially deserves.

The Q-jet uses small primary venturis for excellent part-throttle response and fuel economy, combined with large secondary venturis for full-throttle performance. The design is elegant. The implementation requires careful calibration that the factory often got right, but that deteriorates over decades.

A properly rebuilt and calibrated Q-jet on the correct application is as good as anything else available for a street car. The rebuilding process is finicky — the accelerator pump circuit, the secondary air valve spring rate, the power valve — and getting it wrong results in the stumbling and stalling that gave the carburetor its bad reputation.