This Billet LT4 Supercharger Lid replaces the upper supercharger lid on all GM LT4 Superchargers for a quick and clean install. Nitrous and fuel are injected into each cylinder from inside of the supercharger lid, providing direct port style distribution. Systems come standard as a single stage with jetting for 100 to 300WHP. This lid is made from a solid piece of billet aluminum with 1/8NPT machined directly into the lid, which makes it easy to add a direct port water/methanol later on.