Steel C/M Spring Seat - 1.650 x .630 x .570

The Steel C/M Spring Seat (PAC-S133) is a precision-engineered valve spring component designed for high-performance engine builds and race applications. This spring seat serves as the load-bearing foundation for coil springs in cylinder head assemblies, ensuring consistent spring pressure and eliminating deflection under extreme valve train stress. Whether you're building a naturally aspirated performance engine, preparing a vehicle for track duty, or restoring a classic muscle car with modern internals, this component is critical for maintaining proper valve timing and preventing catastrophic valvetrain failure.

Manufactured from hardened steel, the Steel C/M Spring Seat features dimensions of 1.650 inches outer diameter by 0.630 inches inner bore by 0.570 inches height, making it compatible with mid-range spring packages common in small-block and mid-block applications. The precision-ground surfaces ensure zero runout when installed over the valve stem, critical for maintaining concentricity of the spring assembly. Its compact 0.02-pound weight contributes minimal inertial mass while the steel construction resists deformation from sustained high-RPM operation and prevents spring surge that can lead to valve float.

Technicians and engine builders favor this spring seat for LS-family engines, small-block Chevrolets, and similar platforms requiring aftermarket cylinder head packages. Installation requires careful orientation during assembly to ensure the beveled or flat seating surface matches your specific valve spring configuration. Verify spring seat diameter and bore dimensions against your cylinder head specifications before ordering, as improper fitment will compromise valve control and engine reliability. This component is essential when upgrading to performance camshafts, high-lift rockers, or increased boost levels where factory springs and seats are insufficient.