[Jay S]

The shim only goes on the front side of the thrust bearing. On first one I did I was expecting there to be equal shims on the front and the back. I tried that , then also checked the alignment to see where the crank is suppose to be positioned. It usually comes out that all the shimming is on the front side. Pontiac apparently indexed the throw positions of crank from the back thrust face of the block on all their engines. I think it is possible on some cranks you could need a very very thin shim (a few thousandths) on the back side on some cranks with shim stock. I have not had to do that yet, wouldn’t be surprised if some others have though.