Description
If you’re running your engine hard, stock valves and springs become a liability. The PROX 28.SIS4336-2 Kit replaces worn or inadequate OEM components with nitrided steel valves and premium chrome vanadium springs engineered to handle sustained high-RPM operation without fatigue or valve float. This is a direct bolt-on upgrade that uses your existing retainers, bases, and seals—no machine work required.
Built for forced induction, naturally aspirated builds, or any engine seeing serious track time, this kit delivers the reliability and durability demanded by professional racers and serious enthusiasts.
- Nitrided steel valves
- Increased surface hardness
- Reduced wear resistance
- Premium chrome vanadium springs
- Higher RPM durability
- Engineered spring rates
- OEM-compatible installation
- Bolt-on fitment
- Uses existing retainers
- Compatible with OEM bases
- Compatible with OEM seals
- Intake or exhaust configuration
- MPN: 28SIS43362
