Hays crankshaft adapter sleeves allow you to bolt a GM automatic transmission to a Ford engine or an older GM automatic transmission to an LS-series engine. These adapter sleeves insert into the crankshaft flange with no modifications to give you the correct distance and pilot size to use a torque converter of the transmission type being installed. Use of this adapter keeps from possibly damaging the input shaft of your transmission when doing a transmission swap. These are manufactured from precision CNC-machined top quality steel.