In-Tank Fuel Pump and EFI Sending Unit for G-Body LS Swap
When tackling an LS swap in a G Body, reliable fuel supply and accurate level feedback are critical so this EFI Sending Unit and In-Tank Fuel Pump installs directly into the factory tank flange to remove adapter plates. A calibrated 3/8 inch sender matches the stock float resistance curve to keep gauge readings accurate during cornering or hard acceleration. The Walbro 255 liter per hour pump supports 550 horsepower and resists ethanol corrosion to maintain stable pressure under load. Installers get a direct fit to Grand National, Monte Carlo, Cutlass and G8 flanges so tank modifications stay minimal and seals remain factory tight.
Precision Matching of Stock Float Mechanics
The 3/8 inch feed line sending unit is engineered to replicate the original float geometry and resistance curve found in G Body fuel tanks. By adhering to the factory calibration profile, the unit delivers gauge readings that mirror stock behavior through cornering and rapid acceleration. Tight machining tolerances and a stable mounting surface prevent sensor wobble or false readings, ensuring drivers always know their true fuel level. This careful replication removes the need for dash gauge recalibration and preserves the familiar response of the factory display.
Robust Pump Design for Consistent Flow under Ethanol Fuels
The integrated Walbro 255 liter per hour pump sustains the pressure demands of up to 550 horsepower without cavitation or flow drop off at wide throttle openings. Its impeller geometry and controlled internal clearances promote rapid system refill and maintain stable delivery even when road conditions change suddenly. Constructed from corrosion resistant materials, it stands up to ethanol blends over extended service intervals, keeping flow rates steady and preventing lean conditions that can damage injectors or engine internals. This reliability supports aggressive driving styles and long duration runs without fear of fuel starvation.
Factory Flange Integration for Direct Fitment
This assembly mounts directly to GM Grand National, Monte Carlo, Cutlass and G8 tank flanges, eliminating adapter plates or welding. Installers simply align the unit with existing pilot holes and reuse the stock O-ring seal for a leak-free connection. By preserving the original flange interface and fuel line routing, the design maintains underbody appearance and reduces potential leak paths. The result is an OEM-style installation that keeps the tank shell intact and minimizes custom fabrication time.
Streamlined Installation to Preserve Tank Structure
With minimal modifications required, this EFI upgrade installs in a few hours and avoids extensive cutting or reinforcement of the tank shell. Reusing the factory seal and mounting points not only cuts labor time but also preserves the structural integrity of the tank, which helps prevent vapor leaks and corrosion over the long haul. The straightforward process and direct fit design allow G Body enthusiasts to complete their LS conversion quickly, returning the vehicle to reliable operation with modern fuel injection capability.
Enjoy precise fitment and lasting reliability with this EFI upgrade, and for a related FLT product browse our Fuel Fitting Kit for G-Body.