Interesting read. See section Bushings vs Needle Bearings. Almost makes a case for high pressure pump too when using Bushings “in most applications, where the loads and speeds are extremely high, the Jesel stance is the needle-bearing roller is a must. Unlike a rod or main bearing, there is not enough oil pressure available to a lifter roller to sustain an oil film needed between an axle and bushing to keep it from galling or wearing.”
https://www.jbspowercentre.com/wps/w...ydraliclifters