2017-2026 L5P Duramax Billet Exhaust Manifolds

Billet manifolds in place of cast

Wehrli builds these 2017-2026 Duramax manifolds from TIG-welded, CNC-machined billet steel to replace the restrictive cast factory parts. Wehrli says the better exhaust flow quickens turbo spool, lowers exhaust temperatures and adds power and economy.

Ports are gasket-matched to the heads and internally divided, so they suit stock or ported heads. Outlets line up with factory-style up pipes and are designed to pair with Wehrli's 2 in. stainless high-flow up pipes (sold separately).

Wehrli lists SEMA certification SC-WCF01-0174 for this part.

Who it's for

2017-2026 Duramax owners replacing cracked or restrictive manifolds, or building for more power.

Key specs (per Wehrli)

What's included

• Left and right billet exhaust manifolds
• New gaskets
• ARP 12-point fasteners and washers for the heads
• Assembly lube
• 1/8 in. NPT port plug

Fitment notes

• Fits 2017-2026 Chevrolet Silverado / GMC Sierra 2500 HD and 3500 HD with the 6.6L L5P Duramax.
• Wehrli says they also fit 2019-up L5D Duramax 4500/5500/6500 medium-duty trucks.
• Pairs with Wehrli 2 in. stainless up pipes WCF100624 (sold separately).
• Up pipe fastener kits are sold separately (WCF100199).
• California: Wehrli does not ship this part to California.

Professional install available at Powertech Diesel, Idaho Falls — call 208-542-7793.