Description
If you’re running high-RPM applications or pushing your engine beyond stock parameters, OEM valve springs and valves become a limiting factor. The PROX 28.SIS1337-2 kit replaces both with nitrided steel valves and premium chrome vanadium springs engineered to handle sustained high-RPM stress without fatigue or float. This is a direct upgrade for serious builders and racers who need reliability under extreme conditions.
- Nitrided steel valves
- Reduced wear profile
- Chrome vanadium springs
- High-RPM rated
- Intake or exhaust configuration
- OEM retainer compatible
- OEM base compatible
- OEM seal compatible
- Bolt-on installation
- Professional fabrication optional
