THUNDERMINGO Quadrajet 4-BBL Carburetor Electric Choke — 750 CFM Direct Replacement for Chevy 305/350 (1904R/1906R, Pre-Jetted)

THUNDERMINGO’s new Rochester-style Quadrajet 4-BBL carburetor is a direct-replacement electric-choke unit designed to fit 1980–1989 Chevy small-block 305 and 350 V8 engines and most applications that originally used 1904R/1906R Quadrajets.

This replacement carburetor reproduces the Quadrajet 4MV electric-choke design with a roughly 600–800 CFM flow range (commonly rated at 750 CFM) and comes pre-jetted for many stock configurations. It is built to replace GM part numbers 1904R and 1906R on passenger cars and light trucks from the early-to-late 1980s where the Chevrolet bowl entrance and linkage style are used. The unit is supplied fully assembled and tested but does not include electrical plugs or AC throttle kick-up hardware.

Will this carburetor fit my Chevy 305 or 350 engine?

If your vehicle originally used a Rochester Quadrajet 1904R or 1906R with an electric choke and the Chevy-style bowl entrance and linkage, this THUNDERMINGO unit is intended as a direct fit. Confirm the factory part number and physical mounting style before ordering to avoid compatibility issues.

• Designed to replace 1904R / 1906R Quadrajet 4MV electric choke units.
• Fits many 1980–1989 Chevrolet 305 and 350 c.i. V8 installations.
• Compatible with EGR-equipped systems when the original used EGR.
• Not suitable for computer-controlled fuel systems or marine use.

What are the key specifications and pre-installed jet sizes?

The THUNDERMINGO Quadrajet is engineered to operate in the 600–800 CFM band, with most examples set near 750 CFM for stock small-block applications. The factory pre-installed jets and components give a baseline tune suitable for many 305/350 setups, but tuning is often necessary after installation to match intake/exhaust and camshaft changes.

• Typical flow range: 600–800 CFM (most commonly 750 CFM).
• Main jets: 190; Idle jets: 120; Air correction jets: 190.
• Auxiliary venturi ≈ 7 mm; choke tube (venturi) ≈ 31.7 mm; needle valve size: 3.3.
• Electric choke-equipped and ready to be wired; no electrical plug included.

What should I know about installation, tuning, and limitations?

The carburetor ships fully assembled and has been bench-tested, but it does not include installation instructions. Basic mechanical skill and a few specialty tools are recommended; you may prefer a professional mechanic for final tuning and adjustment. This product is not intended for computer-controlled engines, and it lacks the AC kick-up assembly and wiring connectors that some late-model vehicles used.

• No written installation instructions included; use reputable online guides or a mechanic.
• Tuning (idle mixture, float level, choke calibration) may be required after install.
• Not for computer-controlled fuel systems or marine applications.
• Verify carburetor size and linkage style match your existing unit before purchase.

How do I confirm this is the right replacement and prepare before buying?

Measure and compare your current carburetor’s throttle linkage, bowl entrance, and mounting flange to the Rochester Quadrajet 1904R/1906R pattern. Cross-reference OEM part numbers and note whether your vehicle uses EGR and an electric choke to ensure compatibility. If you need wiring plugs or AC kick-up hardware, plan to source those separately.

• Compare OEM part number (1904R/1906R) and physical mounting details.
• Check for Chevy-style bowl entrance and linkage orientation.
• Confirm whether your vehicle uses EGR and electric choke functionality.
• Order missing electrical connectors or throttle kit parts if required.

Who this is for: The THUNDERMINGO Rochester Quadrajet replacement is aimed at classic Chevy owners, restoration shops, and DIY mechanics who need a direct-replacement 4-BBL electric-choke carburetor for 1980–1989 small-block 305/350 V8 engines originally equipped with 1904R/1906R Quadrajets. It’s ideal for projects that require a stock-style carburetor footprint and performance baseline, provided the vehicle is not computer-controlled and the buyer is prepared to handle final tuning or enlist a professional for precise setup.