SMG "Big Boy" Drop-In Fuel Pump for 2014+ Silverado/Sierra

The SMG "Big Boy" Drop-In Fuel Pump is a high-output low-side fuel system upgrade for 2014+ Chevrolet Silverado and GMC Sierra V8 trucks. Built around a modified GM OE-style fuel pump module, the system combines a Walbro 535 (Hellcat) fuel pump with upgraded wiring for a factory-style installation without modifying the fuel tank, factory wiring, or fuel supply lines.

Key Features

Modified GM OE-style drop-in fuel pump module
High-output Walbro 535 (Hellcat) fuel pump
Upgraded internal wiring
No fuel tank, factory wiring, or fuel supply line modifications required
Designed to increase low-side fuel volume and pressure beyond common LT4 retrofit configurations
Compatible with pump gasoline and ethanol fuels
Can be combined with auxiliary fueling systems for additional fuel capacity

Tested Performance

SMG testing has demonstrated support for over 750 WHP on E85 with stock LT4 injectors, an LT4 high-pressure fuel pump, and a 32% camshaft fuel lobe.
Actual fuel system capacity and horsepower support vary based on tuning, fuel pressure, injector and HPFP capacity, boost level, supporting modifications, and operating conditions.

Fitment

2014+ Chevrolet Silverado V8
2014+ GMC Sierra V8
Standard Cab, Extended Cab, and Crew Cab applications
Correct cab configuration must be selected to receive the proper fuel pump module.

Tuning & Fuel Pressure Notes

Tuning is required.
SMG may provide vehicle-specific baseline HP Tuners settings when available but does not provide individual tuning support.
SMG recommends approximately 50 PSI as a baseline, with 50-60 PSI generally used for higher-demand combinations.
Fuel pressure requirements vary by vehicle and engine combination.
Many factory fuel pressure regulators begin bypassing fuel near 5 bar, which can reduce available fuel volume if excessive pressure is commanded.
Desired pressure, maximum pressure, duty-cycle, ECM, and FSCM calibration settings should be addressed as applicable.

Important Notes

Do not run below approximately 1/4 tank during performance driving. Low fuel levels may increase the risk of pump cavitation or fuel starvation under high demand.
Designed for pump gasoline and ethanol fuels only. Other alternative fuels may damage seals and internal components and void the warranty.
Each Big Boy module is assembled and tested to order. Typical build time is 5-7 business days before shipment.
Includes a 90-day warranty to the original purchaser against manufacturer defects. Improper installation, physical damage, unsupported fuels, and tuning-related issues are not covered.

Note: Published horsepower results are based on SMG internal testing and are not guaranteed. Actual results depend on the complete fuel system, calibration, vehicle combination, fuel, and operating conditions. Proper tuning is required.