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Wehrli Custom Fab S400/S300 Twin Duramax LB7 Kit (2001-2004)

Fits: 2001-2004 GM/Duramax

Cannot be shipped to California
Pricing: $3,817.10

Customize Your Item

- Choose Year of Vehicle -
 * required
- Choose Basic Color* -
- Choose Two Coat Colors $75* -
- Select Turbo 400 -
 * required
- Color Match Comprsr Cover S300 -
 * required
- Color match comprsr cover S400* -
 * required
- Select Intercooler Brand -
 * required
- Select Turbo 300 -
 * required
- Select External Wastegate -
 * required
- Select Fuel Filter Relocation Ki -
 * required
- Select Lower Oil Pan With Bung -
 * required
- Select Up Pipes* -
 * required
- Coolant Pipe Core Charge $150.00 -
 * required
- Select T4- T6 Turbo Heat Blanket -


Compound Turbo Kits (also known as Twin Turbo Kits) for the 2001-2004 LB7 Duramax have become one of the most popular upgrades for daily drivers and towing rigs. The S300/S400 Kit replaces the factory turbo charger with a stronger, more robust fixed vane type S300 Turbo. Properly spec'd setups can operate very well at lower horsepower ratings and still tow extreme weights. But you also have the option to push the horsepower level to over 1000 RWHP. (with proper supporting modifications) Kits are available without turbo chargers but we will need to know what you are planning to use, and in some cases, may need your turbos sent in for the build process.

This kit Requires Custom Tuning for proper operation and performance. We recommend kits to be installed by a qualified diesel performance shop or mechanic.

Below we have spec'd out a few popular choice option kits:
1. Daily Driver, Heavy Towing Combination- S364.5 SXE with .90 Turbine Housing paired with a S480 Borg Turbo Wheel and 1.15 Turbine Housing. This setup works best in the 400HP-700HP Daily Driver, Heavy Towing Combination. This combo is capable of towing loads in the 15-18,000 Range and can still be turned up to lay down 700HP. With the addition of an internally waste gated .83 Turbine Housing for the S300 Turbo, the kit can be pushed to the 750HP range.

2. Daily Driver, Mild Towing Combination- S366 SXE with .90 Turbine Housing paired with a S480 Borg Turbo 1.32 Turbine Housing. This combo will operate well in the 500-850HP Range and is still capable of towing upwards of 15,000lbs with correct driving techniques. Adding the .83 internally waste gated housing is a good choice if you do plan to tow heavy but also want to push the 800HP Range.

3. Daily Driver, Racer, Light Towing Combination- S369 SXE with .90 turbine housing paired with a S480 Borg Billet and 1.32 turbine housing. Are you a weekend warrior drag racer that still have a boat to tow? This is the setup for you. With supporting modifications, this combination will break 1000 RWHP but is still very well capable of towing 12,000 lbs. Highly modified engine lower end would be necessary as well as serious fuel upgrades to make 1000 HP, but this setup is a great, street able, daily driver that can impress when needed.


-5" Intake
-Dry Air filter
-Outer Wears Pre-Filter Cover
-SS Oil Feed and Drain Lines with Fittings for both Charger
-Cast T4 Pedestal & Spacer with Hardware
-Heavy Duty Atmosphere Turbo Pedestal
-4" Turbo Down Pipe
-3 1/2" Turbo Hot Side Cross Over Pipe
-3" Hot Side Intercooler Pipe
-3" Cold Side Intercooler Pipe
-3" One Piece Y-Bridge
-One Piece 3 ½" Cold Charge Pipe Between Turbos with V-Band Connections
-Coolant Tank Kit with Low Coolant Sensor
-Modified Upper Coolant Pipe
-O-ring seals
-Silicone Boots
-T-Bolt Clamps
-V-Band Clamps
-Heat Wrap & Clamps
-High Temp Black Coating
-Powder Coating


Shipping Information

  • Item Requires Shipping
  • 80.0 lbs.
  • W19.0000” x H15.0000” x L36.0000”

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