Im talking about the weird looking spacer ring in this pic. Im doing an lt1 t56 swap and need to know if this is necessary http://i111.photobucket.com/albums/n...ird/Pix968.jpg

 

Thats a flywheel shim. That flywheel was probably resurfaced at one point and the shim was added between the flywheel and crank to make up for the amount of material removed. Some people say they aren't needed and that the hydraulic clutch will compensate, but personally I'd put it back on if it was on there before.