5.9 Magnum pushrod measuring questions

Is your motor assembled to the point to where you can spin the oil pump with a drill while rotating the crank with a ratchet and socket? If it is, try that to pump up the lifters. You can manually pump them by putting a little pressure against them to simulate down pressure that a push rod would provide. Do that to a few random lifters and check the measurements with the checker pushrod to see if there is consistency of the lengths.