I searched on this topic and found many hints/tips. I bought the Edelbrock top end package for my 289 Ford (Performer RPM hydraulic tappet, non roller kit) The literature states "Caution: Do Not Pump up lifters prior to installation Pumping up lifters may result in bent pushrods, bent valves, and or other damage upon initial start up." Another note in the Performer RPM Cam document speaks about valve adjustment and setting preload. I am assuming that the lifter is not "pumped" up for this and this just sets the preload. I was planning on buying two solid lifters (I dont have any old lifters available to make a solid lifter to check from) Installing the solid and using clay I should get greater than .080" to be safe using a head gasket. Am I on the right track? I also wanted to know the forums consensus on preload. Edelbrock states 1/4 turn after zero lash, Comp cams (whose roller rockers I bought states 1/2 to 1 turn) I was going to follow Edelbrocks advice since it is their lifters. Anything I am missing? Thanks, Brian.