Wehrli 2004.5-2005 LLY Duramax 4in Intake Kit with Air Box - Bengal BlueWCFab 2004. 5 2005 GM LLY 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