In-Tank Fuel Pump Module 400LPH Retro-Fit Series

The In-Tank Fuel Pump Module 400LPH Retro-Fit Series from HOLLEY is engineered for enthusiasts and builders upgrading fuel delivery on carbureted or legacy fuel-injected platforms. This module solves the critical challenge of retrofitting high-flow fuel pumps into factory tank environments without extensive modifications. Whether you're building a classic hot rod, restoring a muscle car, or upgrading a vintage truck, this 400 LPH pump assembly provides the reliable fuel supply needed for naturally aspirated and mild boost applications without requiring complete fuel system redesign.

The 400 LPH (liters per hour) capacity delivers adequate fuel volume for engines up to approximately 400 naturally aspirated horsepower, making it ideal for small-block V8s, big-block cruisers, and turbocharged four-cylinders in the lower boost range. The in-tank design eliminates external pump mounting and heat soak issues associated with frame-mounted pumps, while the retro-fit architecture integrates into existing fuel tank baffles and pickup tubes with minimal modification. Internal check valves and safety shutoff features protect against vapor lock and fuel spillage, ensuring safe operation across varied driving conditions and ambient temperatures.

Mechanics and engine builders favor this module for carbureted restorations, EFI retrofits on older vehicles, and complete fuel system upgrades where tank removal is impractical. The compact dimensions allow installation into most vintage and modern tank configurations without clearance conflicts. Proper fuel line sizing and regulator selection are essential—pair with a quality pressure regulator (typically 5–7 PSI for carburetors, 40–60 PSI for EFI) and appropriate fuel filter to maximize component lifespan and engine reliability. Installation requires basic mechanical skill and standard hand tools; consult your vehicle's fuel system schematic for electrical connections and tank-to-carburetor routing.