Upgraded Valve SPG 4G6322001 AM001 VALVE SPRING Valve Spring for High RPM Engines Valve spring performance is very important for valves to follow accurate cam profile. 1. Compatible with High RPM Engines As engine rpm rises, valves must open and close in a shorter time and so requires stronger Valve Springs in order to apply sufficient pressure. 2. Ensuring Close Contact When changing to high lift cams, proper contact between the valves and the cams can be lost which leads