Product Description Specifications COMP Cams' Valve Spring Shims are manufactured from the highest quality shim stock available. The shims are heat-treated to withstand radical camshaft lobe profiles, and are a great way to equalize the installed height of valve springs. Category: Engine Components>Valve Springs, Retainers Core: N LTL: N MPN: 4742-100 Proposition 65: N Special Order: Y