SMG "Big Boy" Drop-in Fuel Pump for 14+ Silverado/Sierra

SMG “Big Boy” Drop-In Low Side Fuel Pump Module – 2014+ Silverado / Sierra

Meet the ultimate OEM+ fueling upgrade for late-model GM trucks — the SMG “Big Boy” Drop-In Fuel Pump Module.
This system bridges the gap between LT4 fueling and full standalone or auxiliary fuel systems, providing a massive increase in volume and pressure while retaining a factory-style fit and finish.

Factory Fit. Race-Level Flow.

The Big Boy module starts with a modified GM Original Equipment pump assembly, upgraded with:

• A High Output Walbro 535 (Hellcat) fuel pump

• Reinforced upgraded internal wiring

• Precision-calibrated factory-style fuel pressure regulation

• Direct drop-in design — no cutting, splicing, or tank modification required

Simply remove your OEM module, drop ours in, and update your tune for maximum results.
No need to alter your tank, wiring, or fuel supply lines.

Performance Proven

Tested and validated to support 750+ wheel horsepower on E85 with stock LT4 injectors, LT4 HPFP, and a 32% cam lobe.
With more boost, tuning refinement, and additional supporting mods, results can climb even higher.

• Bridges the gap between LT4 fueling and standalone/auxiliary systems

• Perfect when combined with an SMG Aux Fuel Kit for extreme fueling capacity

• Must-have upgrade for forced induction and ethanol builds

• Ideal pairing with LT4 injectors and either the OEM or oversized LT4 HPFP for the ultimate OEM+ bolt-on setup

Fitment

Fits 2014–2018 Silverado and Sierra V8 models, including:

• Silverado 1500 Custom / High Country / LS / LT / LTZ / SSV / WT

• Sierra 1500 Base / SLE / SLT / Denali

Note: May fit some early 2019 trucks with the previous-generation tank design — confirm with your installer before ordering.
Cab selection required (Standard Cab vs. Extended/Crew Cab) to ensure proper fitment.

Build Quality & Testing

Each Big Boy pump module is hand-built and tested in Texas using in-stock OEM and better components.

All Pumps are fully tested and must pass our benchmarks before  prior to shipment to verify performance and integrity. That means no DOA's, every single pump we ship works as it should and we guarantee it! 

• Made to order: allow 5–7 business days for assembly before shipment

• Shipping method selected at checkout only affects transit time

• Refer to store policies for made-to-order and cancellation terms

Tuning and Operation Notes

All Big Boy systems require tuning to optimize fuel pressure and flow.
While they can be run on stock calibrations, and will outperform the OEM module immediately, proper calibration ensures maximum benefit and reliability.

• Uses OEM-style basket and FPR

• GM regulators typically bleed off at ~5 bar (72 psi) — exceeding this can cause pressure loss

• Commanding 50–60 psi typically supports even high-power builds due to the pump’s huge volume

• Review and adjust Desired Pressure, Max Pressure, Duty Cycle, FSCM, and ECM pressure tables accordingly

• Avoid running below ¼ tank during performance driving — the pump moves fuel faster than the saddle transfer system can keep up

If you notice fuel pressure drop at high demand, your tuner can resolve this by adjusting commanded pressure to stay within regulator limits.

Warranty

• 90-day limited warranty for the original purchaser against manufacturer defects

• Warranty does not cover improper installation, physical damage, tuning errors, or use of unapproved fuels

• Pumps must be returned to SMG for inspection and validation prior to any authorization

For service inquiries, contact info@smgspeed.com with your order details.

Fuel Compatibility

• Designed for pump gasoline and ethanol fuels (E85)

• Not approved for methanol, race gas additives, or other alternative fuels
  (Use of unapproved fuels may damage internal seals and void warranty)

Summary

✅ Drop-in replacement — no cutting, splicing, or tank mods
✅ Supports 750+ WHP on E85 with stock LT4 fueling hardware
✅ OEM fit with high-output Walbro 535 (Hellcat) pump
✅ Assembled, tested, and tuned for real-world power
✅ Ideal for supercharged or turbocharged E85 builds
✅ Made in Texas, built to perform