I'm thinking some metal was left inside the block which contaminated the new bearings. Either that, or the block itself had some blockage feeding the crankshaft. Hopefully you get it all figured out. Just don't let it get you down. Pull the bottom end out and see which bearing spun. If rod #2 spun again, its likely a problem with the block somewhere. #3 spins first under oil starvation issues from my experience.