Tomei Valve Spring Sheet Shim Set for the Mitsubishi 4G63 and Subaru EJ20. These spring sheets adjust the amount of load applied to each spring. By adjusting all springs to the same uniform spec, blueprinting can be done to achieve higher engine RPMs for full race engines. Without spring load adjustment, the valve springs can surge under high load and lead to loss of power. In the worst case scenario, it can disengage the valve keepers from the valve stem and create major damage in the valvetrain.

Comes with 8 Spring Sheets