We always suggest running at least 2 full turns of pre-load (about .080" ) on the Magnum hydraulic roller lifters. These lifters have about .180" of travel in them so there is plenty of room. If you don't have adjustable rockers I would try a little longer pushrod. We have found that less than .080" pre-load just about always has a slight tick. Good Luck!
Kevin @ Hughes Engines