What size is the Chevy fuel line?
Across Chevrolet vehicles, fuel line size varies by model, year and engine. The most common diameters you’ll encounter are 3/8 inch (0.375") for modern fuel-injected systems and 5/16 inch (0.3125") for many older carbureted setups. Always verify with the vehicle’s service manual or by measuring the line.
Why size differs by model and era
Chevrolet used different fuel-delivery configurations over the decades, from carbureted engines in the 1960s through 1980s to modern multi-point injection. The diameter of the hard line and any hose sections are chosen to meet the engine's flow needs and pressure, so there isn’t a single universal size for all Chevys.
Common sizes you’re likely to encounter
Below are the sizes you’re most likely to see when replacing fuel lines on Chevrolets. The numbers refer to the outside diameter of hard steel lines or the inner diameter of hoses that fit corresponding fittings.
- 3/8 inch OD (0.375") — Most common on newer EFI systems and many trucks; used for main supply lines and feed to regulators or rails where higher flow is needed.
- 5/16 inch OD (0.3125") — Frequently found on older carbureted Chevrolets and some mid-year models; adequate for standard carburetor fuel delivery.
- 1/4 inch OD (0.25") — Seen on some very early or economy configurations; less common today and typically limited to smaller feeds.
- 1/2 inch OD (0.5") — Rare for primary lines on most Chevys; may appear in specific high-volume runs or long-lumen sections in large trucks.
These sizes refer to the hard line diameter or the hose size compatible with the respective fittings and flares. Always verify the exact size for your particular model before purchasing replacements.
How to determine your Chevy’s fuel line size
To ensure accuracy, follow these steps:
- Consult the factory service manual or official workshop diagrams for your exact vehicle (year, model, engine) for the recommended fuel-line size.
- Measure the line yourself with calipers or a ruler to determine the OD of a straight section; or measure the hose ID if replacing hose segments.
- Match the size to new parts by vehicle application or bring the old line or a photo to parts counter to verify compatibility.
Safety reminder: Work with fuel systems only after depressurizing lines, disconnecting the battery, and ensuring you’re in a well-ventilated area. Use proper fittings and follow torque specifications when replacing lines.
Frequently asked questions
Is there a single Chevy fuel line size?
No. Chevrolet used multiple sizes across decades and models. The most common diameters are 3/8 inch OD for modern EFI and 5/16 inch OD for many carbureted engines, with occasional 1/4 inch or 1/2 inch segments in specific configurations.
How do I replace a fuel line if I don’t know the size?
Identify the exact model and year, reference the factory diagrams, or measure the line. When replacing, order by vehicle application (year, model, engine) or bring the old line to the parts counter. If in doubt, consult a professional.
Summary
Chevy fuel line size varies by generation and configuration. The most common diameters you’ll encounter are 3/8 inch OD for modern EFI systems and 5/16 inch OD for many carbureted engines, with other sizes appearing in certain configurations. Always verify with the service manual, diagrams, or by measuring the line itself before purchasing or installing replacements to ensure safe operation.
