Our Quadrajet Build Process

Here is an overview of what we offer for each section of the Quadrajet and a complete build.

The Quadrajet has three main sections

• Base plate
• Air horn
• Main body

Each section receives specific inspection, cleaning, repair, and calibration work.

Base Plate Repair

The base plate is disassembled by removing the primary and secondary shafts. Primary shafts become loose in the original aluminum base from age and wear, so bronze bushings are installed to help prevent vacuum leaks. The shafts are reinstalled with the throttle blades and set to open to 90 degrees for best performance. Circuits can also be modified for air/idle mixture and air bypass on larger-cam, higher-compression engines.

The base plate is ultrasonically cleaned, blasted, and resurfaced on the bottom to ensure a good seal to the intake.

Available repairs include:

• Broken screw repair
• Stuck shafts and bent butterflies

Air Horn

The air horn is the top section of the Quadrajet and contains many working components. Like the base plate, a common auto-parts-store kit does not include what this section needs for proper performance.

The air horn is removed along with the primary choke and secondary air valves. The shafts are removed, and the secondary air valve cam and tension spring are replaced. Vent tubes are removed, cleaned, checked for blockage, and reinstalled.

Most air horns are warped from over-tightening, so we resurface them to ensure a good seal to the main body. When an application does not require a choke, the front choke flap can be removed. Secondary air valves can also be modified to provide a smooth transition as they open.

The Main Body

This is where the action is.

The main body is completely disassembled, soaked, and ultrasonically cleaned. Every passage is measured and modified as needed to match the engine and driving situation. A Quadrajet placed on a high-compression, big-cam engine will not idle correctly without the proper modifications.

The build can include:

• Jets and primary rods exchanged and sized for proper calibration
• A new check ball verified to seat
• A new high-flow needle and seat
• A new float set to the correct level
• A new accelerator pump with a garter spring compatible with today’s fuel
• A new fuel filter with spring and gasket
• A new power piston spring matched to the cam and compression
• New gaskets, including base-plate-to-intake and air-horn-to-air-cleaner gaskets
• A new primary choke pull-off
• Sealed fuel wells

It All Goes Back Together

After each section is built, the Quadrajet is carefully reassembled and every component is checked for proper operation. It is shrink-wrapped, placed in a double-wall heavy-duty box, packed securely, and shipped with insurance. Adjustment instructions are included.

What Level Build Do You Need?

Level 1 Build

Level 1 is for a stock engine with the correct Quadrajet for the year, make, model, and engine size. The carburetor receives enhancements that address known issues, including sealed fuel wells. Jets and primary rods are selected for today’s ethanol-added fuels.

Level 2 Build

Level 2 is for engines modified with a mild cam, headers, aluminum intake, higher compression, head porting, or a Quadrajet that was not originally made for the engine. It is designed for a good idle, smooth transition throughout the power band, and strong performance when the secondaries open.

Level 3 Build

Level 3 is built for maximum performance while retaining excellent street manners. It uses our advanced techniques to deliver the maximum power your combination can support.

Coloring Process

Our coloring process was developed through years of testing with chemicals and liquids that are safer for us and the environment. The main body and air horn are cleaned and stripped before going through a multi-stage dipping process that restores color to the original castings. Zinc chromate plating is also available for the body and air horn.

External hard parts are zinc-plated and dipped in chromate solution for a gold or silver appearance.

These carburetors and parts can be more than 50 years old and many have lived a hard life. We do everything possible to produce a beautiful finish, but each carburetor is unique and will finish differently. Our goal is always to deliver a great-running and great-looking Quadrajet.

Finish Options

Plating With Body Color

Premium Plating With Zinc-Plated and Colored Body