Wehrli 01-04 Chevrolet 6.6L LB7 Duramax S400 Twin Turbo Kit (No Turbo) - Gloss White

If you're looking to significantly boost the performance of your 2001-2004 Chevrolet Silverado or GMC Sierra with the 6.6L LB7 Duramax engine, this Wehrli twin turbo kit is a solid option. This kit is designed to work with an S400 series charger and your stock IHI turbo, creating a compound setup that can support up to 1000 rear-wheel horsepower with the right supporting modifications. It’s a popular choice for daily drivers and tow rigs that need more power, better fuel economy, and improved exhaust gas temperature (EGT) control, all while maintaining a turbo spool that feels familiar.

Wehrli has put together a comprehensive package here, including everything you need to get the S400 charger integrated, minus the S400 turbo itself. You'll find a custom powder-coated coolant overflow tank with all the necessary hoses and a low coolant sensor, plus silicone boots and t-bolt clamps for secure connections. The kit also includes a durable Y-bridge with bead-rolled ends for a strong seal, a 4-inch ceramic-coated downpipe for improved exhaust flow, and stainless steel oil feed and drain lines. The 5-inch intake with a dry air filter and Outerwears pre-filter cover helps ensure clean air gets to the turbos, and the 3.5-inch cold side charge pipe and 3-inch intercooler pipe are designed for efficient airflow.

This kit is made in the USA and features a tough gloss white powder coat finish for a clean look under the hood. While it’s designed to work with stock fuel systems for setups like the S475/Stock IHI combination, more powerful turbo and fuel combinations will require supporting modifications, including a built Allison transmission for setups aiming for 750+ rear-wheel horsepower. Please note this kit is not CARB approved and cannot be shipped to California.