The combination of the triple primary venturi and the sophisticated primary main metering circuit deliver light throttle and cruise mixtures that just can't be matched by off the shelf generic Holley carburetors. A Q-Jet properly tuned, is just a wonderful fuel and air mixer. The bad reputation and negative pet names for Q-jets comes from three primary issues IMO. 1. Since any Q-jet will physically bolt on any manifold for a spread bore carb, many, many Q-jets were mixed and matched over the decades and just dead wrong in so many ways for the application. With thousands of factory calibrations, how could this possibly work correctly?. 2. Early Q-jets did have some issues. The goofy initial needle and seat design, the well plug leaks, the float leverage issue, and a few others were addressed and corrected as production moved forward. 3. You need to have some understanding of carburetors and fuel delivery and some mechanical skills to work on a Q-jet. Modular Holley carburetors are extremely simple to take apart and jet. Also no metering rods to play into the tuning mix. For someone with minimal or beginners level skills, a Holley can be made to run decent pretty easily. A Q-jet is on a higher skill level to get right but you are rewarded with a great performing carburetor that has many people just shaking their head in amazement that a stock looking GM carburetor can perform that flawlessly.
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