I need to collapse lifters on a 390 with non adjustable rocker arms. It is necessary to collapse lifter to check correct push rod length. What method should I employ. Thanks Jerry

 

I just finished this. You need the appropriate pushrod checker. A good set of feeler gauges. A pair of channel locks to use for applying pressure to bleed down the lifters. I set my pushrod checker length to 9.570" feeling that nothing would be less than that. Put the checker in place, pry the rocker back to bleed down the lifter, and hold while using the feeler gauges to see what the clearance is. Several articles said to add those numbers and then subtract 0.05" to get you pushrod length.