Clean your block and crank with soap and water before final assembly. Use wire brushes that reach thru all the passages. The damage to your bearings is from left over crap from the machining process that got flushed thru your oiling system. even if the machinist cleans the block, you should clean it again. Most shops dont do a very good job of cleaning cranks and blocks unless they are assembling it themselves.
You should check that crank clearences with micrometers, not plastigage.