Measuring for pushrod length on a flat tappet, stock rocker motor. Using the checker, the range is 7.8 to 8.8 Verify stem heights are close, I like within. 010. That means my head guy takes pride in his work and we can use one length pushrod on this bank. Spin the checker out until zero lash. Zero lash is when you have light drag rotating the pushrod and the rocker had no slop. Count the number of turns. In example. 17.5 x.050 for each turn. Here we get .875, take .875 add to 7.8 and you get 8.6