The Chevrolet Performance Flexplate to LS Engine Crankshaft Adapter/Spacer is used when installing a non-LS engine automatic transmission, built before 1997, to an LS engine. The LS engine crankshaft flange is 10mm shorter in relation to the end of the bell housing flange, requiring this spacer to be used to bridge the gap between the crankshaft and torque converter when the bellhousing is bolted to the block. Note: Longer bolts are required and sold separately (unless stated otherwise)