[madmaxx]

There is no such thing as an "anti- pump" up lifter. The way you prevent a lifter from pumping up is set the lash on the lifter to about 1/8 turn after zero lash. Bottom line is if the valves do float and the lifter does it job and takes up the slack it can only "pump up" 1/8 turn. Keith Craft sells some high rev lifters, they have a cir clip for the retaining ring instead of the wire clip which can pop out if. KC also makes some other modifications to the lifters which I am not familiar with but they work.

Anything above 5600 rpm with a hydraulic lifter and you are in valve float territory. You go above 6000 rpm with anything but a mild street cam and they are going to float.