2017-2026 L5P Duramax CP3 Conversion Kit
Can I pick up my order or have it installed at your shop?
Can I pick up my order or have it installed at your shop?
Absolutely. We offer local pickup on most products and full professional installation at our shop in Washington, MO. Whether you just want to grab your parts or have our techs handle the install, we’ve got you covered. Give us a quick call at636-429-7020or message us to schedule a visit — we’ll make sure the parts are ready when you arrive.
How do I know if this part fits my vehicle?
How do I know if this part fits my vehicle?
Unsure if it’ll fit? No problem — that’s what we’re here for. Send us your vehicle’s year, make, and model, and we’ll verify fitment before you order. We can also point you toward compatible upgrades or supporting parts if needed.
What if I need to return a product or it’s defective?
What if I need to return a product or it’s defective?
Most unused items can be returned within 30 days in their original packaging. Some products are covered by a manufacturer’s warranty as well. If something arrives damaged or doesn’t meet your expectations, just let us know — we’ll help you get it replaced, refunded, or repaired. (Tracking updates are also emailed automatically once your order ships.)
What's the lead time on custom or fabricated parts?
What's the lead time on custom or fabricated parts?
Many of our parts are built to order — especially fabricated or performance components. These can take additional time to produce before shipping. Lead times vary by manufacturer and demand, but we’ll always keep you updated along the way. If you’re working on a tight schedule, reach out before ordering at636-429-7020and we’ll confirm current availability or estimated ship dates.
Description
Description
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.
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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
