I have no experience w/ bushed lifters, but my understanding is a bushed lifter needs pressurized oiling.
My KB block doesn't feed oil to the lifters at all. Just splash and drainback oiling. I have Isky Red Zone lifters w/ needle bearings from 2006 before they offered bushed lifters. Haven't had any issues w/ them.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 4 speed, Dana 60
'71 Demon 340, no drivetrain, on blocks behind the barn
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
| 
