2017-2026 L5P Duramax CP3 Conversion Kit

Break past the limits of the stock HP4 pump on your 2017-2026 Chevrolet/GMC 6.6L Duramax (L5P) with the WCFab CP3 Conversion Kit. Built for trucks running bigger turbo kits and injectors that have maxed out the factory high-pressure fuel system, this conversion opens the door to more power with a proven CP3 platform — sized to match your build from stock-replacement duty all the way to competition.

Why Choose the WCFab L5P CP3 Conversion Kit?

• Beats the HP4 Ceiling – The ideal fix for trucks that have reached the limits of the stock HP4 pump and want more power.
• Four Pump Sizes – Sportsman, 10mm, 12mm, and 14mm options cover everything from a failed-HP4 replacement to built competition engines.
• Proven CP3 Platform – Reliable, tunable fueling with real-world power levels validated in WCFab's own shop trucks.
• Scales With Your Build – Pairs with WCFab drop-in and compound turbo kits and Exergy injector packages for a matched fuel-and-air combo.

Choose Your CP3 Pump Size

Part # Pump Size Best For Power Target WCF100455 Sportsman Replacing a failed HP4, or stock / Exergy 30% over injectors with stock or drop-in VGT setups, or the S364.5 / S369 Drop-In Fixed Vane Turbo Kits Up to 750 HP to the wheels WCF100456 10mm Pairs with S372, S463, and S467.7 kits running Exergy 60% or 100% over injectors Up to 850 HP to the wheels WCF100457 12mm Works best with S472 and S476 kits and Exergy 100% over injectors Proven over 1000 WHP WCF100458 14mm Built competition engines using power adders, big single or custom compound chargers with custom injectors Pushing the limits of the L5P platform

Fits These Models

Fits the 2017-2026 Chevrolet/GMC 6.6L Duramax (L5P) — model years 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, and 2026. Order the pump size that matches your turbo and injector setup using the table above.

Key Features at a Glance

• Four Pump Options - Sportsman through 14mm.
• Up to 1000+ WHP Capable - Sized to your build.
• CP3 Conversion - Moves past the HP4 limit.
• Turbo & Injector Matched - Pairs with WCFab kits.

Notes

• Requires an aftermarket low-pressure / CP3-compatible lift pump with 15–20 PSI of pressure.
• Not compatible with the OEM L5P in-tank pump or high-pressure lift pumps designed for use with HP4 injection pumps.
• Custom tuning is required.
  

Questions? We're Here to Help.

Have questions about upgrades for your L5P Duramax? Contact FASS Motorsports and we'll get you dialed:

Phone: 636-429-7020

Email: info@fassmotorsports.com