I have always had rear main drip on every BB I ever did, not bad, but annoying. When I redid my Hemi, it came from MP with the anti-leak rear main bearing. I duplicated the v groove on my new bearing with a sharp chisel and a light touch, can't tell em from the factory ones, they probably do them the same way. Anyway, first rubber sealed BB in 20 years and a dozen engines, without a leak and over 7K miles so far. Can't swear that is the answer, but it costs nothing when building the engine. Mopar calls them anti-leak rear main bearing, maybe they are onto something?
