I wouldn't attempt this modification without the availability of a bridgeport type milling machine and some nice parallel blocks of different heights. The one I did mine on also had a 12" riser which made the job so much easier. If you attempt to use hand tools you risk having the drills walk or not drill straight. I have never done it this way but I guess its possible if your super careful. There is a description on how to in this thread, do a search for ( bearings for oil cross-drilled Nord engine). Good luck. Peter.