A Guide to Replacing the Carburetor on a 1973-1980 Chevrolet C20 Suburban
Solve engine problems and improve performance by choosing the right new aftermarket carburetor for your classic square body Suburban.
- Symptoms like rough idle, hesitation, and hard starting are strong indicators of a failing carburetor on this vehicle.
- For reliability on a street-driven truck, a new Edelbrock carburetor is a highly recommended upgrade over a remanufactured unit.
- Holley carburetors are better suited for high-performance or racing builds that require extensive fine-tuning.
- Plan on having your new carburetor tuned after installation to ensure it runs correctly with your specific engine.
Is it Time for a New Carburetor?
The original carburetors on these Suburbans are now decades old. Gaskets and seals can dry out and fail, especially with modern ethanol-blended fuels. This can cause a range of problems from annoying to serious. If your truck is hard to start, idles poorly, hesitates when you accelerate, or gets terrible gas mileage, a worn-out carburetor is a likely culprit.
🎬 Watch this video to diagnose a crank no start condition.Fuel Leaks are a Fire Hazard
If you smell strong gas fumes around your engine or see liquid fuel on the intake manifold, your carburetor may be leaking. Do not drive the vehicle until this is fixed, as a fuel leak creates a serious risk of an engine fire.
Common Symptoms of Carburetor Failure
- Hard Starting: Having to pump the gas pedal many times to get the engine to start, especially after it has been sitting for a while. This can happen because the fuel in the carburetor's bowl evaporates or leaks out.
- Rough Idle: The engine shakes or idles unevenly when stopped. It might even stall at stoplights.
- Hesitation or Stumbling: When you press the gas pedal, the engine stumbles or bogs down before picking up speed. This is common when going up a hill or putting the engine under load.
- Black Exhaust Smoke: Black smoke from the tailpipe indicates the engine is running "rich," meaning there's too much fuel and not enough air. This will also cause poor fuel economy.
- Poor Fuel Economy: A noticeable drop in your truck's miles per gallon can be caused by an inefficient or leaking carburetor.
- Flooding: The engine won't restart when it's hot because too much fuel is being dumped into it. This was a known issue with the original Rochester carb floats failing.
Choosing an Aftermarket Carburetor: Repair or Upgrade?
Since new OEM Rochester carburetors are no longer available, your choice is between a remanufactured stock-style unit or a new performance-oriented carburetor. Your budget and how you use your Suburban will guide your decision.
Brand Tiers & Quality
Tier 1: New Performance Carburetors (Edelbrock, Holley)
- Edelbrock: Often recommended for daily drivers and mild street trucks. Edelbrock carburetors are known for being very user-friendly, reliable, and holding a tune well. They are designed to work well right out of the box with minimal tuning, making them a great choice for those who are not expert mechanics.
- Holley: The traditional choice for maximum horsepower and racing applications. Holley carbs offer a high degree of tunability for squeezing out every bit of performance, but can be more complex. Some users note they can be more prone to fuel leaks over time compared to an Edelbrock.
For a mostly stock C20 Suburban with a 350 or 454 engine used for regular driving, an Edelbrock Performer series carb (600-750 CFM depending on engine) is a very popular and reliable upgrade.
Tier 2: Remanufactured Stock-Style Carburetors (Uremco)
- Uremco: This company remanufactures original carburetors to factory specifications. This is the most budget-friendly option and provides a direct, stock replacement. However, owner reviews show that quality can be inconsistent; some units work perfectly, while others have issues like leaks or missing parts right out of the box.
| Part Type | Estimated Cost | Notes |
|---|---|---|
| New Aftermarket (Edelbrock/Holley) | $267.65 - $487.10 | Best for reliability and performance. May require tuning. |
| Remanufactured (Uremco) | $200 - $350 | Stock replacement. Quality can be inconsistent. |
| Shop Labor for Installation | $150 - $300 | Typically 1.5-2.5 hours of labor. |
Frequently Asked Questions
Can I replace the carburetor myself?
Yes, this is a very DIY-friendly job for someone with basic tools and mechanical ability. The process involves removing the air cleaner, disconnecting linkages and hoses, unbolting the old carb, and installing the new one. There are many helpful videos online showing the general process. 🎬 See this walkthrough of a carburetor replacement on a 350. Just be sure to clean the intake manifold surface where the new carburetor will sit to prevent vacuum leaks.
What does CFM mean and which one do I need?
CFM stands for Cubic Feet per Minute, and it measures how much air the carburetor can flow. A stock 350 V8 generally runs well with a 600 CFM carburetor for street use. A larger 454 V8 might benefit from a 750 CFM carburetor. Choosing a carb that is too large can actually hurt performance and drivability.
Will I need to tune the new carburetor?
Almost certainly, yes. Even carburetors that are calibrated from the factory will need adjustments for your specific engine and altitude. At a minimum, you will need to set the idle speed and the air/fuel mixture screws. An improperly tuned new carb can run worse than the old one. If you are not comfortable doing this, a professional mechanic can tune it for you.
🎬 Watch: How to fine tune an Edelbrock on your Chevy.Are there any recalls on the carburetor for my Suburban?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database show no safety recalls specifically for the carburetor on the 1973-1980 Chevrolet C20 Suburban.
Helpful Videos
Technical Specifications
OEM Part Numbers: 7043210 17056204 17057204 17058213
Original carburetors were typically Rochester 2-barrel (2GC) or 4-barrel (Quadrajet M4MC) models. Common aftermarket replacements are square bore, 4-barrel carburetors with CFM ratings from 600 to 750, often with an electric choke.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.