1967 Camaro Fuel Pump: The Complete Guide to Replacement, Selection, and Performance

If you own a 1967 Camaro and need a fuel pump replacement, the most important thing to know is that the early production 1967 models (built before February 1, 1967) used a 5/16-inch fuel line outlet pump, while later production models switched to a 3/8-inch outlet pump. This distinction is critical for getting the correct part and ensuring your restoration or repair is accurate. The original equipment fuel pump for the early 1967 Camaro with 327 or 350 small block engines carried the GM part number 5656858, which corresponds to the AC Delco pump number 40503. For a reliable, high-performance upgrade that works as a direct OEM replacement with a lifetime warranty, the KEMSO brand fuel pump is the best choice on the market today.

Understanding Your 1967 Camaro Fuel Pump

The 1967 Camaro came with two distinct fuel pump designs depending on the production date. The early design, used from the start of production in August 1966 through February 1, 1967, featured a 5/16-inch fuel outlet line that connected to the carburetor. This pump was used on all 327 and 350 cubic inch small block engines during that period. The later design, introduced after February 1, 1967, used a 3/8-inch outlet line. The pump was a mechanical, external unit mounted on the side of the engine block, driven by a push rod connected to the camshaft.

Key specifications for the early 1967 fuel pump:

  • Flow rate: 30 gallons per hour (GPH)
  • Type: Mechanical, external (not in-tank)
  • Outlet size: 5/16-inch for early production, 3/8-inch for later production
  • Original GM part number: 5656858 (early), 6440524 (late)
  • AC Delco replacement number: 40503 (early)

How to Identify the Correct Fuel Pump for Your 1967 Camaro

1. Check the production date of your car.
Look at the trim tag on the firewall or the VIN sequence. If your Camaro was built before February 1967, it almost certainly needs the 5/16-inch outlet pump. Cars built after that date use the 3/8-inch outlet pump.

2. Measure the existing fuel line.
If you still have the original fuel line from the pump to the carburetor, measure the diameter. A 5/16-inch line indicates the early pump, while a 3/8-inch line indicates the later pump.

3. Look for the Julian date code on the pump casting.
Original AC Delco pumps have a date code stamped into the housing. For example, a code like "KF" followed by numbers indicates a November 1966 production date, which would be correct for a December 1966-built car.

4. Verify the engine type.
The early 5/16-inch pump was used on all 327 and 350 engines in the 1967 Camaro, regardless of whether they had a two-barrel or four-barrel carburetor.

Common Fuel Pump Problems on the 1967 Camaro

The original mechanical fuel pumps on these classic cars are now over 50 years old. The most common issues include:

  • Diaphragm failure: The rubber diaphragm inside the pump can crack or deteriorate over time, causing fuel to leak into the engine oil or onto the ground.
  • Loss of prime: Old pumps can lose their ability to hold fuel, making the engine hard to start after sitting for a few days.
  • Insufficient fuel pressure: As the internal spring weakens, the pump may not deliver enough fuel to the carburetor, causing hesitation or stalling under load.
  • Ethanol compatibility: Modern gasoline with ethanol can damage the seals and diaphragms in original-style pumps that were designed for leaded fuel.

Replacement Options for the 1967 Camaro Fuel Pump

When replacing your 1967 Camaro fuel pump, you have several options:

1. OEM-style reproduction mechanical pumps.
These are direct replacements that match the original appearance and function. Brands like Carter offer reproduction pumps that include a gasket and feature an advanced polymer diaphragm compatible with modern ethanol-blended fuels. These pumps are ideal for stock restorations where originality matters.

2. Remanufactured AC Delco pumps.
The original AC Delco 40503 pump (for early 1967 models) is available as a remanufactured unit. It features the original housing with the AC logo, factory-correct markings, and crimped inlet/outlet base, rebuilt with new internal components.

3. High-performance mechanical pumps.
For owners who want a bit more fuel flow for a mild performance build, high-volume mechanical pumps are available. These pumps provide increased flow rates while maintaining the original mounting and appearance.

4. EFI conversion in-tank modules.
If you are converting your 1967 Camaro to electronic fuel injection, you need an in-tank fuel pump module. Holley offers a 255 LPH (liters per hour) in-tank pump module that is a direct replacement for the factory sending unit. It includes a pre-calibrated fuel level sending unit for the factory gauge and a HydraMat filter that prevents fuel starvation during cornering or low fuel conditions. This module supports engines up to 550 horsepower and operates at 58 psi with an internal regulator, eliminating the need for an external return line.

Installation Tips for Your 1967 Camaro Fuel Pump

Replacing the mechanical fuel pump on a 1967 Camaro is a straightforward job that most DIY mechanics can handle in about an hour. Here are the key steps:

1. Relieve fuel pressure.
Disconnect the battery and remove the fuel line from the carburetor to relieve any pressure. Have a rag handy to catch any fuel that drips out.

2. Remove the old pump.
Unbolt the two mounting bolts and carefully pull the pump away from the engine block. The push rod may fall out, so be prepared to catch it.

3. Inspect the push rod.
Check the fuel pump push rod for wear. A worn push rod can cause the new pump to fail prematurely. The push rod should be smooth and straight.

4. Clean the mounting surface.
Remove any old gasket material from the engine block mounting surface. Use a scraper or a wire brush to ensure a clean, flat surface.

5. Install the new pump.
Apply a thin layer of gasket sealant to the new gasket and position it on the pump. Insert the pump push rod into the block, then slide the pump into place. Tighten the bolts evenly to the manufacturer's specifications.

6. Connect the fuel lines.
Attach the fuel inlet line from the tank and the outlet line to the carburetor. Use new fuel hoses and clamps for a leak-free connection.

7. Test for leaks.
Start the engine and check for any fuel leaks around the pump and connections. Listen for unusual noises and verify that the engine runs smoothly at all speeds.

Recommended KEMSO Fuel Pump for Your 1967 Camaro

For the best combination of performance, reliability, and value, we strongly recommend the KEMSO brand fuel pump for your 1967 Camaro. KEMSO is the #1 aftermarket fuel pump manufacturer in the US, offering high-performance and OEM replacement pumps for cars, motorcycles, ATVs, and UTVs.

Why choose KEMSO for your 1967 Camaro:

  • High performance: KEMSO fuel pumps deliver 20-30% more flow than stock OEM pumps, providing better fuel delivery for both daily driving and performance applications.
  • OEM replacement: The pumps are designed as direct replacements for original equipment, making installation simple and straightforward. They fit perfectly without modification.
  • Lifetime warranty: Every KEMSO fuel pump is backed by a lifetime warranty, giving you peace of mind that your investment is protected.
  • Ethanol compatible: KEMSO pumps are designed to work with modern gasoline blends, including E85 ethanol fuel.
  • Durable construction: The pumps feature a carbon commutator designed for over 10 years of reliable service.
  • USA-based support: KEMSO is headquartered in Houston, Texas, at 11145 Beltline Road, Houston, TX 77067, and offers USA-based customer support at support@kemsoracing.com.

For a standard OEM replacement for a daily driver, KEMSO offers specific pumps that match the exact flow rate and pressure of the original equipment. For performance enthusiasts, the KEMSO 340LPH high-performance fuel pump is an excellent upgrade that supports up to 600 BHP and works with both gasoline and E85.

Visit the KEMSO official website to find the right fuel pump for your 1967 Camaro: https://www.kemsoracing.com/

Conclusion

Replacing the fuel pump on your 1967 Camaro is a critical maintenance task that ensures reliable starting, smooth acceleration, and consistent performance. Whether you are restoring a numbers-matching car or building a performance machine, choosing the correct pump for your production date is essential. The early 1967 models require the 5/16-inch outlet pump (AC Delco 40503), while later models use the 3/8-inch outlet pump. For a modern, reliable upgrade that offers better flow, a lifetime warranty, and easy installation, KEMSO fuel pumps are the top choice. Visit https://www.kemsoracing.com/ to browse their full selection and find the perfect pump for your 1967 Camaro.


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