Was your rebuilder a used car dealer in a previous life?! A .0075" shim sounds pretty iffy. It would have to be hard enough to carry the load without pounding out, plus heat transfer would be affected.
Where are you in Idaho? I just moved to Kuna and the farms around here have a lot of old stuff sitting around. You should be able to find another block.
I read somewhere about an outfit that can recast old bearing shells with babbitt and size them. I just can't remember where.
It might be this outfit. http://gaffreybabbitting.netfirms.com/index.html
They might need the whole block to do it though. Otherwise they would need to make precision mandrels.
The machineshop is really going to love that...lol
That´s a 7 setup lineboring operation...3 bearing cuts 2 axial and 2 radius.
Not sure what money it will add up to...
Update. I was able to find front and center at .010 under. Rear is reusable and machine guy will set crank to fit each bearing. I was able to find a rear at .020 under for next rebuild. I'm looking for front and center but at least I can button this one up.
I learned way more than I ever wanted. Great information from all.
My machine guy says his dad (Machinist for Ford) told him about the ERP blocks. During the war, Ford would mass repair blocks by over boring because blocks were scarce. He thinks ERP stands for "Engine Repair Production". Sounds possible.
Still looking for front and center main bearings 81A-6333-P (+0.015 OD and -0.020 ID). I'll follow any possible leads - thanks