1.550" Od. 0.567" Id. 0.060" Thick Hardened Steel Valve Spring Seat Springs They are engineered to be

They are engineered to be "where the oil is" under the most demanding racing conditions

a gilmer kit is a must for street or strip engines

circuit racing and made to withstand extreme use

This planetary gear is fully Rollerized

These Performance Automatic hardened input shafts are custom-forged from 9310 non-twist steel

1.550" Od. 0.567" Id. 0.060" Thick Hardened Steel Valve Spring Seat Springs They are engineered to beAs with all other parts in the valvetrain, the area where the spring sits takes a beating. The old standard shims simply will not hold up to the extreme pressures and high rpm found in today's performance engines. Speedmaster offers this set of valve spring shims to solve this problem and eliminate failures.