What is a 4GC carburetor?
The 4GC carburetor has a fully automatic choke. Originally Rochester identified the 4-Jet carburetors with a triangular tag mounted on the air horn. Early 4-Jet tags were brass, but was changed to aluminum during 1956/57. If no tag is present the last 4 or 5 digits MAY be stamped on the air horn.
How do I identify my 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.
How does a 4 barrel Quadrajet carburetor work?
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. Thus, the Quadrajet acts like a vacuum-secondary carburetor and only delivers more fuel as it is needed.
How do I know what carburetor I have?
The list number is stamped on your carburetor, either on the corner of the airhorn or choke tower or, if it doesn’t have an airhorn, on the mainbody. Remove the carburetor from your vehicle before looking for the list number to easily find the information you need.
Where are the numbers on a Rochester 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.
Does Edelbrock make Quadrajet?
795 CFM Q-JET REPLACEMENT FOR CHRYSLER THERMO-QUAD This Edelbrock Q-Jet carburetor features all-metal construction for no leaks and no hassles. It includes an electric choke along with a 3/4″ 4-hole spacer, throttle lever adapter and fuel line adapter for an easy installation.
What CFM is a stock Quadrajet carb?
750 CFM
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 Quadrajets good carbs?
The truth is, a properly tuned Quadrajet can be just as efficient and reliable as a bolt-on substitute performance carburetor. And because they were used on so many original-equipment applications, they are readily available from many used parts suppliers at a very reasonable cost.
When did the Rochester Quadrajet carburetor come out?
The Quadrajet was actually the successor to the previously-built Rochester 4GC carburetor that was manufactured from 1952 to 1967. This new carburetor was blended with what Rochester knew about carburetors, mixed with ideas from other manufacturers, (spread-bore design and vacuum secondaries). The Quadrajet became an instant success.
When did the 4m Quadrajet replace the Rochester 4G?
And because of its efficiency and excellent balance of economy and performance, the 4M Quadrajet became the standard production 4-barrel carburetor for all GM manufacturers. The Rochester 4G was phased out as the Quadrajet replaced everything except the Holley 4-barrel, which continued on certain Chevrolet applications through 1972.
Where is the part number on a Rochester Quadrajet?
In late 1968, the seven-digit part number was stamped vertically into the main housing First Or Second Generation 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.
What kind of choke does a 4G carburetor have?
The 4G carburetor is equipped with a manually-operated choke valve. Some 4G carburetors are equipped with a vacuum controlled governor to control engine speed (RPM) on heavy-duty truck applications. The 4GC carburetor has a fully automatic choke. Originally Rochester identified the 4-Jet carburetors with a triangular tag mounted on the air horn.