Sierra Electric Fuel Pump 18-7331, Low Pressure, GM Mark V 454/7.4L & 502/8.2L (HU-WT) Engines

The Sierra 18-7331 is a low-pressure electric fuel pump built for GM Mark V 454/7.4L and 502/8.2L (HU-WT) marine engines. It delivers a 45 GPM flow rate at 8 PSI, matching the output of the original low-pressure fuel pump these engines were designed around. The pump body is constructed of metal alloy with plastic and rubber components for the seals and fittings, giving it the durability needed for continuous marine fuel system duty while keeping weight low at 1.35 pounds.

Fuel connections are threaded: a 5/8 inch-18 inlet fitting and a 3/8 inch-24 outlet fitting, both designed for a secure, leak-resistant seal in gasoline fuel systems. The pump uses a tank-mount configuration and is designed as a direct replacement for the factory low-pressure pump on applicable GM Mark V big-block engines, restoring correct fuel delivery pressure and volume without modification to the existing fuel lines or mounting hardware.

This is a low-pressure pump only -- it is not designed for high-pressure MPI fuel injection applications. Confirm your engine's low-pressure fuel pump requirement and the OEM part number it replaces before ordering.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7331
• Type: Electric Fuel Pump
• Pressure: 8 PSI (Low Pressure)
• Flow Rate: 45 GPM
• Inlet Connection: 5/8 inch-18, threaded
• Outlet Connection: 3/8 inch-24, threaded
• Mounting Type: Tank Mount
• Fuel Type: Gasoline
• Material: Metal Alloy, Plastic, Rubber
• Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 1.35 pounds
• UPC: 808282112387

Fitment

• 1994-99 454/7.4L & 502/8.2L (HU-WT) GM Mark V engines, low pressure
• 1992-93 454/7.4L GM Mark V engines, low pressure

Replaces (OEM)

• 3858714
• 3850810
• 3857985

Frequently Asked Questions

What engines does the Sierra 18-7331 fuel pump fit? The Sierra 18-7331 fits 1994-99 GM Mark V 454/7.4L and 502/8.2L (HU-WT) engines as well as 1992-93 GM Mark V 454/7.4L engines, and is designed for the low-pressure fuel pump position on these applications.

Is the 18-7331 a high-pressure or low-pressure fuel pump? It is a low-pressure fuel pump rated at 8 PSI, not a high-pressure pump for MPI fuel injection systems.

What is the flow rate of this fuel pump? The Sierra 18-7331 delivers 45 GPM at 8 PSI.

What OEM part numbers does the 18-7331 replace? It replaces OEM part numbers 3858714, 3850810, and 3857985 on applicable GM Mark V low-pressure fuel pump applications.

What size are the inlet and outlet fittings? The inlet fitting is 5/8 inch-18 threaded and the outlet fitting is 3/8 inch-24 threaded on the 18-7331 fuel pump.

What is the pump body made of? The 18-7331 pump body is metal alloy with plastic and rubber components used for seals and fittings.

How much does the 18-7331 fuel pump weigh? This Sierra fuel pump weighs 1.35 pounds.

How is the 18-7331 mounted? It uses a tank-mount configuration, matching the original equipment mounting arrangement on these GM Mark V engines.

What fuel type is this pump designed for? The Sierra 18-7331 is designed for use with gasoline fuel systems.

What are the physical dimensions of the 18-7331? The pump measures 0.39 x 0.39 x 0.39 inches.

Will the 18-7331 work on a high-pressure MPI fuel-injected engine? No, the 18-7331 is a low-pressure pump and is not intended for high-pressure MPI applications; confirm your engine uses a low-pressure fuel pump before ordering.

Does the 18-7331 come as a complete assembly? Yes, the Sierra 18-7331 ships as a complete electric fuel pump assembly ready to install in the low-pressure fuel pump position.