W2 lifter problem

Hmm. Wierd. Just for giggles, could you pull the pushrods, degrease them, use a little marking dye (called Dykem) or maybe a felt tip marker to mark the tips, clean the oil from the lifter cups, and reinstall. Then turn the engine over by hand and see where the dye or marked is rubbed off. This would indicate if there is a problem with interference between the edge of the cup and the lifter or not. I forgot to ask... What rpm does this engine rev to?