Ratech Solid Pinion Spacer (Crush Collar) GM 12 Bolt

These are excellent for cars that "shock" their rear ends extremely hard during launching, which is common with manual transmissions. The solid pinion spacer will allow your rear end setup to remain constant after repeated hard launches. (Because this piece is setup slightly different than a standard crush collar, please ensure that your gear installer is familiar with installing solid pinion spacers.)