Spring Shims .060x.520 IDx1.300 OD GM LS Series

The COMP CAMS Spring Shim .060x.520 IDx1.300 OD GM LS Series (part number 4788-16) is a precision valve spring shim engineered for General Motors LS-platform engine builds. These shims serve a critical function in tuning valve spring pressure and seat load, allowing builders to dial in exact specifications for both stock and modified powerplants. Supplied as a set of 16 units, these shims provide the flexibility to adjust spring geometry across multiple valve positions or to maintain a full engine's worth of spares during high-performance engine assembly.

Each shim measures 0.060 inches thick with a 1.300-inch outer diameter and 0.520-inch inner diameter, sized specifically for LS-series cylinder head valve spring seats. Manufactured from hardened steel, these shims resist deformation under sustained load—a critical characteristic for engines operating at elevated RPM or boost levels. Correct shim thickness directly impacts valve spring seated height and pressure; undersized or worn shims can lead to loss of spring preload, reduced valve control, and potential valve float at high RPM. The precision thickness and diameter tolerances ensure consistent performance across the entire set.

This set is essential for LS engine builders, machine shops, and serious enthusiasts performing valve spring replacement, head porting, or cam upgrades. Whether assembling a street engine requiring conservative valve spring rates or a race application demanding maximum load capacity, shim selection is non-negotiable. Having a complete set on hand eliminates the need for multiple vendor orders during engine teardown or rebuilds. The 16-unit count provides sufficient stock for single-engine projects with replacements for future maintenance.

LS-platform engines—found in Chevrolet, GMC, Cadillac, and other GM vehicles—demand OEM-quality valve train components. COMP CAMS shims meet the dimensional and material standards expected by machine shops and engine builders nationwide, ensuring compatibility with OEM and aftermarket LS cylinder heads without modification.