Buy Chevrolet Caprice Carburetors

A carburetor (often called a carb or fuel-mixer) sits on top of a Chevrolet Caprice's V-8 engine and blends gasoline with incoming air so the motor can run. From 1966 through 1990, most Caprice models used the four-barrel Rochester Quadrajet-a "spread-bore" unit famous for tiny primary bores that sip fuel at cruise and big secondary bores that gulp air when you floor it. In 1981 GM added the Computer Command Control (CCC) system, turning the Quadrajet into an electronic E4ME/E4MC "feedback" carb that worked with an oxygen sensor to meet emissions laws. The very last factory-carbureted Caprice rolled off the line for the 1990 model year.

The Caprice carburetor is a Rochester Quadrajet 4-barrel. Its "spread-bore" layout pairs small primaries for mileage with huge secondaries for power, giving it 750 CFM on most Caprice 305 cid and 350 cid V-8s (some rare units flow 800 CFM). (en.wikipedia.org, chevelles.com) In 1981 - 1990 cars the electronic E4ME/E4MC version adds a mixture-control solenoid and an electric choke. (charm.li)

Learn more about the Quadrajet design and why many builders still praise its fuel economy potential.

• 1966 - 1976 Caprice: mechanical M4MC/M4ME Quadrajets on big-block and small-block engines. (en.wikipedia.org)
• 1977 - 1980 Caprice (3rd gen start): vacuum-controlled M4MED on 305 & 350.
• 1981 - 1990 Caprice: electronic E4ME/E4MC with CCC. The 1990 307 cid station-wagon engine was the final Caprice to ship with a carb. (charm.li, chevelles.com)

A helpful VIN/engine table appears in many factory manuals; see the free 1991-1996 Caprice service manual PDF (earlier chapters cover carb specs).

1. Air horn - holds choke blade and air bleeds.
2. Float bowl - keeps fuel level steady even in corners. Quadrajet's central float helps off-road stability. (en.wikipedia.org)
3. Primary metering rods & jets - taper-shaped rods slide to meter fuel.
4. Secondary air valve - spring-loaded door regulates giant rear bores.
5. Mixture-Control Solenoid (E4ME/E4MC only) - pulses 10 Hz to fine-tune air-fuel during cruise. (en.wikipedia.org)

At light throttle, only the small primaries feed the engine, giving mileage similar to a two-barrel carb. When you step hard, vacuum drops, the secondary air valve swings open, and CFM jumps for strong acceleration. (hotrod.com)

The CCC computer watches the oxygen sensor and adjusts the solenoid duty-cycle so the carb stays near a 14.7:1 mix-helping Caprice models pass 1980s emissions rules without fuel injection. (en.wikipedia.org)

• Hard hot starts caused by heat-soaked fuel percolation. (justanswer.com)
• Black tail-pipe smoke or fuel smell (stuck choke or rich metering rods).
• Surging cruise speed if the CCC solenoid or oxygen sensor fails. (charm.li)
• Flat spot on launch when accelerator-pump cup cracks-see Hot Rod's tip on pump stem length.

• Keep it clean: a dirty air filter lets grit score the throttle bores.
• Test choke pull-off: with the hose connected, apply vacuum; the choke plate should open smoothly in 1-2 seconds. (charm.li)
• Float level check: factory spec is 1⁄4 inch below the air-horn gasket for Caprice 305 engines.
• Replace soft parts: ethanol fuel dries out the accelerator-pump cup and needle seats every 3-5 years.
• Use fresh gaskets when removing the carb; vacuum leaks around the base cause lean misfire.

• Performance replacements: Spread-bore-friendly units such as the Edelbrock 1906 AVS2 or Holley's Quadrajet-flange 4160 bolt on without an intake swap. See Hot Rod's comparison of Quadrajet vs Holley Sniper EFI for power gains. Read the dyno test.
• Electronic fuel injection kits: Holley Sniper EFI drop-in assumes the same spread-bore pattern, blends modern control with factory intake. (hotrod.com)
• Calibrated jets & rods: Companies sell kits matched to altitude or cam swaps-helpful because Quadrajets are sensitive to engine changes. (hotrod.com)

From 1981 onward, California Caprices used a catalytic converter, charcoal canister, and CCC-controlled E4ME to meet stricter smog limits. The feedback carb's rapid PWM adjustments kept CO and NOx down while retaining a mechanical carb layout. (en.wikipedia.org)

1. Label hoses and connectors before removal.
2. Relieve fuel pressure and catch any spills.
3. Remove throttle-linkage clips (a tiny pick prevents damage).
4. Lift the carb straight up to avoid bending the delicate metering rods.
5. Use a new insulated gasket (keeps fuel cooler).
6. Torque the four base nuts to 12 ft-lb in an X-pattern to prevent air leaks.
   A factory torque chart is available in the 1980-Caprice brochure collection at OldCarBrochures.

General Motors' Rochester Products Division engineered the Quadrajet in 1965, refining it through the 1970s oil crisis and 1980s emissions era. (en.wikipedia.org) The Caprice stuck with carbs longer than many rivals; its 1990 wagon was among the final U.S. full-size cars sold new with a carburetor. (chevelles.com) Today, hobbyists prize the Quadrajet for authenticity in classic "box Chevy" builds and for its surprising street mileage.

• Carb - shorthand in most repair guides.
• Carburettor - British spelling often seen in global articles.
• Fuel-mixing valve - old service-manual term.
• Spread-bore four-barrel - highlights different primary/secondary sizes.
• CCC feedback carb - GM's computer-controlled version.

• Chevrolet Caprice history
• Quadrajet design overview
• Hot Rod carb tech article

These links give deeper dives into Caprice specs, Quadrajet tuning theory, and GM carburetor evolution-all without leading to parts retailers.