Are Quadrajet carburetors any good?

The truth is, a properly tuned Quadrajet can be just as efficient and reliable as a bolt-on substitute performance carburetor. The Quadrajet has many model designations; the most adaptable units were designated as 4M, 4MC and 4MV, and most were rated at 750cfm until 1972 when their rating was increased to 800cfm.

How do I identify a 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 Quadjet carb 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 parts are in a Quadrajet carburetor?

Rochester QUADRAJET 4 Barrel Carburetor Parts.

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.

How a Quadrajet carburetor works?

Quadrajet carburetors have mechanical secondary throttle plates operated by a progressive linkage; the primaries open before the secondaries, and use on-demand air valve plates above the secondary throttle plates. The air valves are connected by a cam and linkage to the secondary fuel metering rods.

What size is a Quadrajet carburetor?

As we mentioned, the Quadrajet is a spread-bore design carburetor, using 1-3/8″ primary bores and 2-1/4″ secondaries. The smaller primary bores give the carburetor better idling and low-load fuel economy. The larger secondary bores are regulated by tapered metering rods which set the air to fuel mixture.

Where are the numbers on a Quadrajet carburetor?

ID numbers for a Rochester Quadrajet carburetor are found next to the throttle level. There should be a metal disc affixed to the carburetor for those in the 1965 to 1968 range, and the number was stamped into the unit without a metal disc on the later-year models. This is the number you need for decoding.

Are Rochester carburetors still made?

In 1995 Rochester became part of Delphi, which in turn became a separate company four years later, and continues to manufacture fuel injection systems in Rochester, now part of General Motors Automotive Components Holdings- Rochester Operations.