ok old skool way of telling if its in the bottomend or head
take a WOODEN broom handle and cut the bristle part off
next sick one end of the handle on the the bottom end of the block(like behind the header, but make sure it is not touching any thing else) then PRESS your ear on the other end of the handle

then repeat for the head (place the handle just under the valve cover)

you will actually hear the noise through the handle and you will definitly beable to tell if the noise is in the head or the bottomend

also if the main journal had a scratch big enough to feel with a finger nail then the bearing is going to go