I have not had that issue with the LS7 lifter and I've cammed several LS motors. What oil pump are you using?
I'm using a melling hplv pump with the standard blue spring.
I had tried to use a hvhp pump before and that liked to flood my cylinder heads and signs of my pan getting sucked dry.
I'm thinking it was all caused by the pac dual spring setup that came with my afr heads.
Higher spring pressure equals more pumping of the lifter.
I found a posting in the corvette forum with the same issue and the resolution to use the different style of lifter.
I have my lifter issues patched right now with some heavier weight oil (40w), pressures are much better and the valve train noise is mostly non existant.
New project in the way, but i plan to install the new lifters once i have the jeep running and on the road.
Next step would be to replace the valve springs with some standard weight ones if this fails to fix the issue.