I too have an engine going together at IMM. 340 hyd. roller engine. @pishta LA’s should be bushed if the chamfers on the lifter bores are deep. Most bores are too deep on LA’s.
I suggest @Torrance1 call Brian.
I am running Comp Retro Hydraulic rollers in my 340 with a XR274HR-10 cam in a stock 69 LA block and have no oiling issues. Lifter bores were all within spec and have very little factory chamfer.
The hyd rollers are junk they are loud and leak down very quickly which causes them to clatter bad on hot and/or cold start up. I have tried every preload known to man they are just poor quality if you did not have to pull the heads to get them out they would already be gone.
I cant recommend the cam either, it's dog down low. Poor valve timing events, intake opens way to late.
