Ive been using Hughes roller rockers and retro roller hydro lifters in a non roller LA block...NOTHING BUT PROBLEMS. Ive had the rocker shafts out 3 different times. Some of the rockers over time will begin to gall and causes the rocker to bind. I can hear it at idle and when I take it apart usually 2 or 3 rockers don't move freely on the shaft. Chucked up in the lathe they clean up pretty nice and are smooth again till the next time. Has never been the same rocker binding twice. Don't get me started on their lifters. 3 different sets and they eventually develop enough wear on the inner plunger to lifter inside bore to cause the plunger to gain excessive clearance, leak down and collapse. Now because of the excessive side load from lifter to pushrod angle, 2 of the lifter bores are egged and the block is useless until the lifter bosses are bushed. I wouldn't recommend hydro roller lifters in a non roller block after my experience and I certainly won't go back to Hughes for rockers. I know some who would never recommend Hydro rollers...I'm starting to lean that way as well on my next build starting next week with an LA factory roller 360 block. I want to run Solid rollers in this one with Harland Sharps up top.