To those of you who would like to eliminate the brass shim which now comes on ISX liners from new. I have a stainless steel shim to replace the brass shim. The block counterbore needs to be machined, to use my shims. A lot of counterbores are worn down on the right side, and should be machined anyway. I worked on one that was worn .010" on the right side, causing the liner to be have .009" protrusion on the left side & .001" below the deck surface on the right side. Needless to say, it would not hold a head gasket. I run them at .014" protrusion, which holds the liner tight, preventing it from moving around and wearing the counterbore surface. I am finding that the ones that are at .009"-.010" protrusion are the ones that wear out the counterbore.