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GM Rochester Quadrajet - Q-Jet City

The Carb Shop Shows Us How To Redo The Q

Mike Petralia Dec 1, 2000
Sucp_0012_02_z Gm_rochester_quadrajet Rebuild 2/23

The first step in any carb rebuild is taking it apart. Remove the nine screws securing the air horn, and then use a small punch to push the accelerator pump pin in towards the air horn so you can remove the accelerator pump arm and rod. After you lift off the air horn, the accelerator pump can be pulled out. Save the spring from beneath it.

There are several good reasons GM chose the Rochester four-barrel "Quadrajet" carburetor to fuel some of the best musclecars ever made. The Q-jet, as it has become known as over the years, is an efficient, simple, and reliable carb that is easy to tune and can make tons of power. The reason a Q-jet is so simple to tune is that it needs very little adjustment to work properly. When equipped on a new car, most of the Q-jet's primary functions were dialed in at the factory so it could work best with the specific engine it was going to fuel. However, since no car has come equipped with a Q-jet for at least 15 years, factory tuning is no longer available and you've got to make that old Q-jet work on your own.

That's where companies like the Carb Shop can help. Although well known for building trick Holley carbs, the Carb Shop is just as adept at tweaking the Q-jet for the street and the track. We stopped in at their Ontario, California, facility and peeked over the shoulder of "Q-jet Boy" Kevin Van Noy as he rebuilt and modified a customer's carb. Check out the tips and tricks he offered, and after arming yourself with one of the Carb Shop's complete Q-Jet rebuild kits you'll feel better about tackling the job yourself-or at least you'll be able to talk to Van Noy and company with a more astute vernacular. When calibrating a Q-jet's fuel curve, the Carb Shop drills and fills some of the factory holes to give your carb the best power and smoothest drivability possible.

A Carb Shop Q-Jet
If you'd rather have a root canal than rebuild your own Q-Jet, the Carb Shop would be happy to do it for you. There are also several tricks and modifications the fuel masters perform on every Q-Jet that would be difficult and expensive for the average-equipped car guy to do. Check out a few of the tricks the Carb Shop is capable of, and decide if you want to DIY or if they can redo your Q.


Carb Shop
Ontario, CA



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