OEM magnum lifters setup

I don't know if its normal or not, but mine does the same thing.

Supposedly some of the lifter bores in these blocks are machined poorly at the top. You might check that out while you've got it apart.

Also, these lifters seem to take an awful lot of preload.

Are you running your engine with the lifters bleeding down? Mine seem to pump up pretty quick as soon as I prime it with the drill. I wonder how it will react on startup....