Image coming soonWehrli 2001-2004 LB7 Duramax Stage 1 High Flow Intake Bundle 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 at 636-429-7020 or 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 at 636-429-7020 and we’ll confirm current availability or estimated ship dates.
Already happy with your intake and down pipe, but the OEM plumbing between the turbo and the engine is still the weak link? The Wehrli Stage 1 High Flow Intake Bundle Kit (Manufacturer Part # WCF100411) for the 2001-2004 Chevrolet Silverado / GMC Sierra 2500HD/3500HD 6.6L Duramax LB7 replaces the restrictive factory Y-bridge and both intercooler pipes with 3" mandrel bent aluminum feeding a TIG welded, CNC machined billet Y-bridge base — a full 3" intake tract from turbo to engine.
Why Choose the Wehrli Stage 1 High Flow Intake Bundle Kit?
- Full 3" tract, turbo to engine – Y-bridge, cold side and hot side all upsized together, so there is no leftover restriction pinching the gains.
- Billet Y-bridge base – CNC machined and TIG welded, Wehrli's signature piece, in place of the restrictive cast OEM bridge.
- Lower EGTs and quicker spool – the point of opening up the whole tract rather than one pipe at a time.
- Boots that outlast the factory ones – upgraded silicone rated for higher pressure and temperature than the failure-prone angled OEM parts, which is where LB7 boost leaks start.
- FPRV block off kit included – the fuel pressure relief valve block off is in the box, not a separate order.
- Works with your OEM style intake horn – the Y-bridge is built for it, so this stacks onto what you already run.
- 14 gauge aluminum – mandrel bent, powder coated in your choice of Wehrli's colors. Made in the USA.
Kit Includes
- 3" fabricated Y-bridge for OEM style intake horn, with TIG welded CNC machined billet base
- 3" passenger (cold) side intercooler pipe
- 3" driver (hot) side intercooler pipe
- FPRV block off kit
- Upgraded silicone boots, clamps and O-rings
Installation Highlights
Bolt-on replacement for the factory Y-bridge and charge piping, retaining your existing intake horn. See the fitment note below before ordering if you have a 2001 truck.
Fits These Models
2001, 2002, 2003 and 2004 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD with the 6.6L Duramax LB7.
Specifications
- Piping: 3" diameter, 14 ga. mandrel bent aluminum
- Y-bridge: fabricated, with TIG welded CNC machined billet base, for OEM style intake horn
- Shipping weight: 15.0 lbs
- Package dimensions: 36" W x 12" H x 12" L, ships in its own box
- Finish: custom powder coat, color selected above
- Made in the USA
Key Features at a Glance
- Full 3" intake tract - Y-bridge plus both intercooler pipes.
- Billet CNC machined Y-bridge base - replaces the restrictive OEM bridge.
- Upgraded silicone boots - no more failure-prone angled factory parts.
- FPRV block off kit included - nothing else to buy.
- Custom powder coat finish - pick your color above.
Notes
- ⚠ 2001 model year fitment — read this before ordering. 2001 trucks have the MAP sensor mounted on the intake runner rather than the bridge. Because Wehrli's bridge is larger than stock, you must relocate the MAP sensor to the port on the new bridge, then drill and tap the runner for a pipe plug (not included) in the original MAP location. The alternative is sourcing a later 2002-2004 LB7 intake runner. 2002-2004 trucks are unaffected.
- Lead time varies by color. WCFab Red, WCFab Grey and Gloss Black are stocked and ship in 3-5 business days. All other colors are made to order on a 10-15 business day lead time.
- Stage 2 adds the 4" intake kit and air box on top of this; Stage 3 adds the down pipe as well.
FASS SKU: [ADD FASS SKU]
Manufacturer Part #: WCF100411
Questions? We’re Here to Help.
Have questions about upgrades for your 6.6L Duramax LB7? Contact FASS Motorsports and we’ll get you dialed:
Phone: 636-429-7020
Email: info@fassmotorsports.com
This part fits the following vehicles:
| Years | Make & Model |
|---|---|
| 2001, 2004 | Chevrolet Silverado 2500 |
| 2001, 2004 | Chevrolet Silverado 3500 |
| 2001, 2004 | GMC Sierra 2500 |
| 2001, 2004 | GMC Sierra 3500 |
Fitment is listed by year, make and model. Some applications also depend on cab, bed, drivetrain or engine — if you are not sure, call 636-429-7020 or send us your vehicle details and we will confirm before you order.
