Late model Big Block Chevrolet engines are originally equipped with exhaust valve rotators. Until now, the only way to make up for the rotator was to stack .300" of shims under the spring. This was not only sloppy, but they also didn't fit well. These seat spacers offered by COMP Cams will locate the spring with an outside step so the spring cannot "walk" around on the head.

Product Reviews for CO4779-8 - COMP