Well checking my lifter preload using the 2 lifters that I took apart and poured out the oil, the preload tolerance is wayyyyy too much I was told. The mini feeler gauge I bought to be able to get under the clip to measure was not even small enough so I cut a piece of .015 feeler gauge material and used that. Well the distance between the clip and the top of the pushrod cap/seat looking at it is at least a 1/4 inch and that would take at least 10 of the feelers on the mini gauge combined to equal that thickness. It still would not fit in there to measure for sure sure exactly what the tolerance is but its ALOT................ He said that preload in excess of .010-.015 is unnecessary and hurtful. I was told to rotate the engine and make sure the lifters were seated all the way and they were indeed. The plunger was all the way down also, bottomed out. So I was told to get some rocker arm pedestal shims , a few boxes to be safe. So I'm just asking here what are you guys experiences with them or knowledge about. I always like to hear more opinions on something so that's why I am posting here. Rocker arm geometry was fine by the way. I did that check using 2 other lifters that had oil in them.