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

Determining pushrod length on a complete roller valvetrain. These are Harland Sharp roller rockers. The major difference is you must set the depth of the adjuster on the rocker before measuring for length. They call for 2 to 3 threads showing under the rocker. This is right at 2 turns. This determines proper oiling to the shaft and valve tips. Then business as usual. Extend checker, count number of turns. Do math and figure out what length pushrod you need. An 8.100 or 8.150 will cover this one.

327 with 1970 lt1 camshaft