FAQ: How To Rebuild A Rochester Quadrajet Carburetor?

How do I identify a Rochester Quadrajet carburetor?

All Rochester Quadrajet carburetors are identified by a seven- or eight-digit GM part number. On units made before mid-1968, the part number was stamped around the outside edge of a round metal tag attached to the fuel bowl.

Is a quadrajet worth rebuilding?

A full and in-depth article of the rebuild process that Jet Performance takes with a Q-Jet Carburetor, by Dragzine.

How many CFM is a Rochester quadrajet?

Quadrajets can range anywhere in between 600 and 800 CFM. Most are rated 750 CFM or higher. Quadrajets are used by many GM street car enthusiasts; however, they are also disliked by just about as many.

Are Rochester carburetors good?

A lot of good and bad has been written about the use of a Rochester Quadrajet carburetor as a replacement four-barrel. Some enthusiasts love them while others avoid them like the plague. The truth is, a properly tuned Quadrajet can be just as efficient and reliable as a bolt-on substitute performance carburetor.

How many CFM is a Rochester 2 barrel?

Carb Sizes and CFM The cfm (cubic feet per minute-a measure of how much air the carburetor can flow) on the Rochester 2G ranges from about 225 cfm in the smallest applications up to what Rochester calls a 435 cfm.

How do you lean out a Rochester carburetor?

How do you lean out a Quadrajet. Big meanie

  1. Fully warm up engine and ensure choke is fully open.
  2. Air cleaner in place.
  3. Set desired idle speed with the idle speed screw.
  4. Adjust the IMS on ONE side to get the maximum possible RPM.
  5. If the above changed the idle sped by more than 40 RPM then readjust the speed.
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What carbs replace Quadrajet?

New Holley Sniper EFI is Direct Replacement for Q-Jet Carb. Holley/MSD is thrilled to announce the release of Sniper EFI Systems for Quadrajet applications, which eliminate the need to continually rebuild 50-plus-year-old Quadrajet carburetors on classic Chevys, Pontiacs, Buicks, Oldsmobiles, and GMCs.

What is a Quadrajet carburetor?

The Quadrajet is a “spread bore” carburetor; the primary venturis are much smaller than the secondary venturis. Most Quadrajets use a vacuum operated piston to move the primary metering rods to control the air-fuel ratio, allowing the mixture to be lean under low load conditions and rich during high load conditions.

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