THUNDERMINGO Rochester 2GC 2-Barrel Carburetor for Chevy 350/400 Large-Base, Electric Choke

THUNDERMINGO's New Rochester 2GC two-barrel carburetor is a direct-fit aftermarket replacement for many Chevy small-block 5.7L (350) and 6.6L (400) engines from the 1970s, featuring an electric choke and a large base flange.

This rebuilt-style carburetor is made to match the Rochester 2GC pattern used on numerous Chevrolet models between 1970 and 1980. It’s intended as a replacement part where the original large-base 2-barrel carburetor (3 11/16" x 2 1/16") is specified. Before ordering, verify your engine displacement and base flange dimensions — this unit will not fit small-base Rochester 2GC carbs or 305/327 engines.

Which Chevrolet engines and vehicles will this carburetor fit?

The THUNDERMINGO Rochester 2GC is compatible with Chevy 5.7L (350 Cu) engines from 1970–1980 and 6.6L (400 Cu) engines from 1970–1975. It fits a wide selection of cars, trucks, and vans that originally used the Rochester 2GC large-base carburetor.

• Common fits: C10/C20/C30 pickups and Suburbans (1970–1980), Impala, Caprice, Corvette, Chevelle, Bel Air, Biscayne, Blazer, El Camino, and various G/P models.
• Also fits some commercial vans and larger trucks listed for 1970–1980 model years.
• Not compatible with 305 or 327 engines or small-base Rochester 2GC flange dimensions.

What are the key dimensions and technical specs I should check?

Confirming physical dimensions is crucial to ensure a proper swap. This replacement uses the large-base footprint and includes an electric choke assembly configured for common OEM mounting points.

• Base flange: large-base only — 3 11/16" x 2 1/16" (check your current carburetor flange before purchase).
• Bolt hole spacing (center to center): 93.5 × 50.5 mm; intake inner diameter: 42.8 mm.
• Choke air horn outer diameter: 78 mm; venturi diameter: 30 mm; two-barrel electric choke design.
• OEM replacement numbers referenced: 17054616, A910, D297-CBCHV, Rochester 2GC pattern.

How do I know this carburetor is a correct replacement for my vehicle?

Match the carburetor to your engine displacement (350 or 400), the vehicle model/year list, and physically compare the base flange size and bolt spacing. If any of these differ, this large-base unit will not fit correctly.

• Verify engine: 5.7L (350) for 1970–1980 or 6.6L (400) for 1970–1975.
• Compare flange dimensions against your original Rochester carburetor (large-base required).
• Check throttle linkage, vacuum ports, and fuel inlet orientation to confirm fitment.

What should I expect when installing and using this carburetor?

This carb is supplied as shown in product images and designed to bolt into vehicles that used the large-base Rochester pattern. Minor adjustments to idle and mixture may be needed during installation and break-in.

• Electric choke requires wiring to the vehicle’s 12V circuit through the appropriate thermal lead or harness.
• After installation, set idle and mixture per your vehicle service manual for best drivability.
• Inspect gaskets, throttle return spring, and vacuum lines; replace any worn components for reliable operation.

Who is this for: This THUNDERMINGO Rochester 2GC large-base carburetor is aimed at classic Chevy owners, restorers, and mechanics rebuilding 1970s small-block 350 or 400 engines who need an aftermarket two-barrel, electric-choke replacement. It’s ideal when the original Rochester 2GC pattern is required and the large-base flange matches your intake manifold. If you’re unsure about compatibility, measure your current carburetor’s base and compare the specifications listed above or contact us with photos for confirmation.