R2 J series engine rebuild

Looking for information as to what parts are still available, are the liners available I have part number 4B6341 ? Bearings main and rod? This brings up the question comparing the D2 parts a complete set of crank shaft bearings for a D2 part number 2F624 and for the R2 5b5730. But if you go to the .030 undersize they both use 5B1879. So does that mean the standard bearings are interchangeable just different part numbers? What about the rod bearings? The crankshafts are the same part numbers. I am comparing serial number 5J4419 and 4J292. I have a D2 engine with bearings if that will work? Thanks