All Crower valve springs are wound from super clean, chrome silicone alloy devoid of impurities and chamfered to reduce imperfections and stress risers that could result in breakage. Crower valve springs are engineered for street or race applications and are the best value in the industry. For those with higher aspirations, Crower is pleased to partner with Eibach for the highest quality, race only valve spring available on the market. Drop-in installation, no machine work required. Works with stock valves and keepers, but be sure to check out Crower's inventory of high quality stainless steel valves listed below.