5/16 Valve Locks - 10 Degree Radius Groove

The PAC Racing Springs 5/16 Valve Locks with 10 Degree Radius Groove are precision-engineered components designed for high-performance engine builders and serious automotive enthusiasts. These valve locks, also known as keepers, are essential fasteners that secure the valve spring retainer to the valve stem, preventing catastrophic valve drop and engine failure during aggressive rev conditions.

Featuring a 10-degree radius groove geometry, these valve locks provide superior contact surface area and positive engagement with the valve stem's lock groove. This design reduces stress concentration points and distributes clamping loads more evenly, enhancing reliability under sustained high-RPM operation. Precision manufacturing ensures consistent groove fitment, eliminating the risk of premature wear or slippage.

Professional engine builders, circle-track racers, and dedicated hot-rodders benefit from the reliability of PAC Racing Springs valve locks. With a 5/16-inch diameter specification, these locks are compatible with standard small-block and mid-sized engine platforms, making them versatile across numerous applications for both competition and street performance builds.