Gord, Not sure that I am completely following you...Did your machinist rough cast your bronze main shells to an undersize then set-up and line bore with main bearings torqued in place? Parts book looks like the rods are cast, no insert....Anyway, if push comes to shove I could probably dig a center main bearing out of an old block and you could possiably get it cast? But then if you were to do that could you bore the center bearing alone and would it align with the front and rear bearings?? I have a couple of those old line boring tools, however they went through a flood in '95 and I haven't gotten up nerve to take the tops off the crates to check them out, probably still have fish swimming around in there.
If you can make the trip over to Leavenworth we would love to have you over for a visit, Bjorg's brother Trond is here from Norway for a coupla weeks but that shouldn't be a problem....928-271-1293 or 509-763-3748