When converting an LS7 with a dry sump to a wet sump oil system, you will need to fill the leftover crankshaft length after changing components. The Holley crankshaft spacer will fill the gap between the damper and the bolt to complete your conversionConverting an LS dry sump engine to wet sump is common when swapping to vehicles that do not offer room for the oil tank. This process requires removal and installation of several OE parts. One dry sump part not changed is the crankshaft. As a result there is extra crank snout length that needs to be compensated for. Holley's spacer goes between the damper and the damper bolt to fill that extra length.