Walbro GSL396 350LPH High Pressure External Inline Fuel Pump 800HP Gas Only

Vehicle Fitment

• Universal - compatible with any gasoline EFI vehicle that can accommodate an external inline fuel pump mounted outside the fuel tank
• Suitable for naturally aspirated, turbocharged, and supercharged EFI applications requiring high-pressure, high-flow fuel delivery
• Designed for return-style fuel systems only - not suited for returnless (deadhead) fuel system configurations

Fitment Notes

• This is an EXTERNAL INLINE pump designed to mount OUTSIDE the fuel tank - it is NOT an in-tank pump. It must be installed in the fuel line between the tank and the engine, typically near the fuel tank on the frame rail.
• For use in RETURN-STYLE fuel systems only - a fuel pressure regulator and return line back to the tank are required. Do not use in returnless/deadhead configurations.
• This pump is designed for GASOLINE only - NOT approved for E85, methanol, or high-ethanol blends. Using incompatible fuel voids the warranty.
• A fuel pre-filter must always be installed between the fuel tank and this pump - operating without a filter will cause premature failure and is not covered under warranty.
• Optimal operating pressure range is 25-70 PSI - verify your fuel system's regulator is set within this range for best performance and pump longevity.
• Pump draws up to 20A - verify the vehicle's fuel pump circuit or relay wiring can handle this current load before installation.
• This listing is for the pump only - the 400-939 installation kit must be purchased separately unless bundled.

Features

• 350 LPH high-pressure flow at 40 PSI (13.5V) - supports up to 800 horsepower in naturally aspirated applications and 650 horsepower in turbocharged or supercharged setups.
• Direct upgrade from the popular GSL392 (255 LPH) - nearly identical overall shape and dimensions for easy swap-in on existing GSL392 installations.
• All-metal construction on the pump body, inlet, and outlet for superior durability compared to pumps with plastic housings in high-heat underbody environments.
• 10mm x 1mm threaded inlet and outlet accept a variety of fittings - compatible with the 400-939 kit's 3/8" hose barb fittings for connection to standard 5/16" fuel hose.
• Identical port threading on both inlet and outlet eliminates orientation confusion during installation.
• Lightweight, compact design simplifies routing and mounting in tight underbody locations.
• QS9000 quality management certified - manufactured to stringent automotive production standards.
• Made in the USA by TI Automotive (formerly Walbro).

Specifications

• Part Number: GSL396
• Brand: Walbro / TI Automotive
• Pump Type: Universal external inline (mounts outside fuel tank)
• Flow Rate: 350 LPH at 40 PSI / 13.5V
• Horsepower Support: Up to 800 HP (naturally aspirated); up to 650 HP (forced induction)
• Optimal Operating Pressure: 25-70 PSI
• Inlet Size: 10mm x 1.0mm female threads
• Outlet Size: 10mm x 1.0mm female threads
• Shell Construction: All-metal
• Current Draw: 20A
• Fuel System Type: Return-style only
• Certification: QS9000
• Fuel Compatibility: Gasoline ONLY (not approved for E85 or methanol)
• Country of Manufacture: United States

Included Components

• 1x Walbro GSL396 350 LPH external inline fuel pump (pump only)

Product Description

The Walbro GSL396 is TI Automotive's highest-flow universal external inline fuel pump in the GSL series, delivering 350 LPH at 40 PSI - enough to support up to 800 horsepower in naturally aspirated gasoline applications and 650 horsepower in turbocharged or supercharged builds. It is the direct successor to the widely used GSL392 (255 LPH), sharing a nearly identical form factor that allows straightforward swap-in on existing GSL392 installations without significant fuel line rerouting. Unlike the GSS series in-tank pumps, the GSL396 mounts externally in the fuel line between the tank and the engine - making it the ideal solution for applications where accessing or modifying the in-tank fuel pump hanger is impractical, or where a secondary boost pump is needed upstream of a surge tank or swirl pot.

Both the inlet and outlet use identical 10mm x 1mm female threads, eliminating the need to track port orientation during installation and accepting a wide range of compatible fittings. When paired with the optional 400-939 installation kit, the pump installs with 3/8" hose barb fittings that connect directly to standard 5/16" fuel line - a common size across most performance fuel systems. The all-metal shell on the pump body, inlet, and outlet provides durability in the underbody environment, resisting heat, vibration, and the corrosive effects of fuel exposure far better than pumps with plastic housings. At 20A current draw, a dedicated relay and appropriately rated wiring is strongly recommended for safe and reliable operation.

The GSL396 is designed exclusively for return-style fuel systems - a fuel pressure regulator and return line back to the tank are required for correct operation. It must not be used in returnless or deadhead configurations. A pre-filter must always be installed upstream of the pump to protect the internals from tank debris. This pump is for gasoline only and is not approved for E85, methanol, or high-ethanol blends. This listing includes the pump only - the 400-939 installation kit, which includes mounting hardware, hose barb fittings, and electrical connectors, must be purchased separately.