Generic 1904R Rochester Quadrajet 4MV 4-Barrel Carburetor for Chevy 305/350 750 CFM Vacuum Secondary with Electric Choke

The 1904R Rochester Quadrajet 4MV is a direct-fit, 4-barrel replacement carburetor with an electric choke and 750 CFM vacuum secondary engineered for 1980–1989 Chevy 305 and 350 engines.

This replacement carburetor restores drivability for older GM small-block V8s by matching the original Quadrajet 4MV footprint while refreshing worn fuel metering with updated components. It’s built for mechanics and restorers who need a practical, bolt-in part that supports EGR systems and simplifies cold starts with an electric choke. The 1904R is offered as a complete assembly with gaskets, ready to swap into vehicles that originally used Rochester Quadrajets, without aftermarket tuning complexity.

Will this 1904R carburetor fit my Chevy 305 or 350 from the 1980s?

Yes — the 1904R is designed as a direct replacement for 1904R/1906R Quadrajet 4MV units and fits most 1980–1989 Chevy/GM 305 and 350 cubic-inch engines. It retains the factory mounting pattern and EGR compatibility, so installation requires no manifold modification on compatible engines.

• Exact bolt pattern and throttle linkage location for 4MV manifolds
• EGR port compatible with original emission plumbing
• Electric choke wiring attaches to existing harness for cold starts
• Intended for standard passenger cars and light trucks using stock Quadrajet setups

How does the 750 CFM vacuum secondary help everyday driving?

The 750 CFM vacuum secondary design provides a balance between fuel economy at cruise and available airflow under load. Vacuum-operated secondaries open progressively with engine demand, producing smoother throttle transitions and reducing the abruptness that some mechanical-secondary carbs can produce.

• Vacuum secondaries delay full airflow until needed, improving part-throttle economy
• 750 CFM rating supplies sufficient air for 305–350 engines without over-carbureting
• Smoother acceleration for street-driven vehicles and daily use
• Less tuning sensitivity than larger, high-CFM racing carburetors

What features support reliable starting and long-term durability?

This unit includes an electric choke that helps achieve consistent cold starts and a stable idle until the engine warms. Components are manufactured from corrosion-resistant materials and undergo durability checks to reduce fuel leaks and wear over time, making the carburetor a dependable replacement for aging Quadrajets.

• Electric choke for predictable cold-weather startups and quicker warm-up
• Sealed gaskets included to prevent vacuum leaks on installation
• Corrosion-resistant metal finishes to extend service life
• Factory-style design minimizes need for aftermarket adapters or modifications

What comes in the box and what will I need to install it?

The package contains the assembled 1904R carburetor plus gaskets and basic mounting hardware, giving you the core parts for a direct swap. No printed instructions are included, so basic carburetor installation knowledge, a torque wrench, and access to a service manual or wiring diagram are recommended for a safe, correct installation.

• Included: carburetor assembly, intake gaskets, mounting studs/bolts where applicable
• Not included: step-by-step instructions or vehicle-specific tuning info
• Recommended tools: hand tools, torque wrench, vacuum gauge for final adjustments
• Ideal follow-up: check for proper fuel pressure and adjust idle mixture after install

Who is this for: The 1904R Rochester Quadrajet 4MV is intended for classic Chevy owners, restorers, and mechanics maintaining 1980–1989 305 or 350 small-blocks who want a reliable, period-correct replacement. It suits drivers who prefer factory-style performance with an electric choke and vacuum-secondaries for street use, and for workshops that need a plug-and-play carburetor compatible with EGR-equipped systems. If you require a direct-fit Quadrajet replacement that balances drivability, build quality, and straightforward installation, this 1904R is targeted to meet those needs.