The Right Way To Use Adjustable Checking Pushrods to Determine Correct Pushrod Length -

To determine the correct rocker arm geometry when using an adjustable checking pushrod on a stud mounted rocker arm cylinder head and a mechanical lifter cam, do the following: Mount the complete cylinder head assembly on the engine, including the head gasket. The cam needs to be installed with the lifters that will be used in the engine. Mark the end of the valve stem with a marking pen or Dykem. Install the adjustable checking pushrod and the rocker arm. Adjust the pushrod so the rocker arm is as low as possible with the bottom of the rocker arm .060” above the hex of the stud or guideplate (whichever is closer). Set the valve lash to the recommended setting and lock the adjusting nut. Turn the engine over by hand until the rocker arm you are working with has moved a complete cycle. Now, remove the rocker arm. The roller tip of the rocker arm will have left a pattern on the end of the valve stem. This pattern of movement should be close to the center of the valve but favoring the intake side of the valve stem. If needed, adjust the length of the pushrod to achieve the correct pattern of movement.

The same process can be used with hydraulic lifters, but make sure the lifter is pumped up solid with oil. The pushrod seat in the lifter should not move. After one or two rotations of the engine, check to be sure the seat has not moved. If so, pump it up and continue your procedure. Once the correct length is determined, you can order the correct pushrods and maybe a couple of spares.