Conversion rod bearings for Babbit rod engines have been around for over 50 years, but they're getting scarce and expensive. I'm working on a conversion to Perkins Diesel engine rod bearings for stovebolts that are plentiful and cheap, but the crankshaft need to be ground to fit the bearings. That's also an advantage, as it can salvage crankshafts that are supposedly "worn out" and ready to be weld-repaired or discarded.
Jerry