I have an LA non roller block retrofitted with the Hughes retro hyd rollers
Hughes Engines.
I think that because of the side load the push rod angle applies to the lifter that it causes excessive leak down over time from the plunger to lifter inner bore clearance opening up. Had to send em all back twice for replacement and they are failing again with probably 10,000 miles on a new 408. Hughes recommends 10w30. They told me to up it to 20W50 should fix the problem...Nope!
Cranking with a remote starter shows that the bad lifters wont pump up. After about 10 revolutions cranking and stopping with a valve closed I can immediately easily move the rocker and feel it bottom out in the lifter. Sent the original set back and they gave me a new set, sent that one back and they gave me another complete set. 6 of the last set have failed now so I'm done with em.
