Wehrli 01-04 Chevrolet Duramax LB7 4in Intake Kit - Fine Texture BlackWCFab 2001 2004 GM LB7 6. 6L Duramax 4" Intake Kit with Air Box. This high flow, fabricated aluminum intake pipe and air box enclosure with dry filter assembly replaces the restrictive plastic factory parts on your diesel for improved engine performance. All new design significantly increases air flow to your turbo producing improved horsepower and torque, quicker throttle response, and cooler intake temperatures by drawing cold air through the inner