During mock-up, a set of COMP Cams pushrod length checkers is perfect for helping determine the right setup for your engine. With a lightweight checking spring in place of the real valvespring, and some layout dye or a Sharpie mark on the tip of the valve, rotate the engine over with a testing pushrod in place. Adjust the pushrod length until the wear pattern across the tip of the valve is shortest. Regardless of whether it is centered on the valve, the shortest sweep pattern reveals the pushrod with the best geometry. Shoot for .060 to .080 inch as the very widest acceptable pattern.