A few months ago I swapped out the lifters in my motor (used but supposedly in good condition) as they were making noise. The motor sat for some time (protected) so we figured the possibility of a collapsed lifter was causing my problems. When I swapped in new lifters, my buddy told me to swap in a set of roller rockers at the same time. The problem was that the rollers required a longer stud as the rocker arm nuts were only being held on by a couple threads. The motor sat while I ordered the parts (first time ordered studs too long ). I removed the studs, installed new ones, set the rocker arm preload and then again with the engine running and up to temp....., I still get what sounds like a lifter knock and not much oil up top. The cam is getting tons of oil as I can see it through the windows in the head and the gauge is usually 60 psi or more (high volume, high pressure pump). My buddy started looking at the old rocker arm studs and noticed that 14 of them looked great, but two were worn where the rocker arm rides (looked like lack of lubrication), the problem is that since I did not expect to have problems with them, I did not mark which valves they went to. Have any of you had problems with worn rocker arm studs (especially on a BBC) and if so, what was the cause? I'm getting ready to pull the motor again and send it to a machine shop if I can't figure out why I can't get rid of the "noise". Any suggestions?