I prefer Mercury assembly lube for needle bearings. It can be hard to find as I think they may have dis-continued it for awhile? I found out my local Merc dealer could get it & stocked up. I like it better than OMC (vasoline) as it just melts in hot weather & doesn’t hold the bearings as well. If you are just talking about general lubrication for assembly like pistons, rings, etc. I use 50/1 oil. Just like I mix with the gas. I don’t care for anything in the engine other than that. Just my opinion!
Dan in TN