Originally Posted by ChevroletSS
Do you take the tool and act like your doing a valve adjustment until you get the right length
No. You install rockers on one cylinder with the adjustable pushrod. Then you use machinist dye or a colored marker to the end of the valve stems. You crank or roll the engine over with the valve adjusted and adjust the pushrod until the pattern shows contact on the center of the valve stem. Then remove the rocker and check the length against the stock pushrod to see how much difference is needed. Lots of various lengths available in pushrods to get close to what your measurement shows.