PAC-S135-16 1.270 in. OD – 0.680 in. Locating Diameter – 0.570 in. ID – 0.060 in. Thickness

1.270 in. OD – 0.680 in. Locating Diameter – 0.570 in. ID – 0.060 in. Thickness Valve Spring Type Dual Outside Diameter 1.270 IN First Step Diameter 0.680 IN Second Step Diameter 0.570 IN Material Chrome Moly PAC Racing Valve Spring Seats and Cups PAC Racing valve spring seats and cups are a great way to prevent dancing springs, which would tear up your aluminum heads. High-performance racing engines place extreme pressure on the springs. These retainers are essential for use on aluminum heads. They fit the inside or outside diameter of the springs, preventing spring seat movement.