Any of the NORS (New Old Replacement Stock) bearings available on Ebay from manufacturers like Federal-Mogul, TRW, Clevite, Vandervell, original equipment GM, etc. would be my first choice. Just make sure the size is correct and the shaft is round and not scored. Once the upper bearing half is rolled out, some careful measuring with a dial caliper can check for out of round and taper of the main bearing journals. It's not quite as accurate as a micrometer, but there's no room to use a mike with the crankshaft still in the block, and no practical way to lower the crank enough to do so. There are several Melling M-45 oil pumps listed on Ebay most of the time, and those pumps are also "best quality" choices. In 60+ years of engine building, I've only seen two actual oil pump failures and both of those involved a piece of metallic debris jamming the pump so tightly it sheared off the drive. I have seen badly scored pumps from ingesting metal too small to actually lock up the works, but those pumps still moved oil well enough to keep the engine lubricated.
If there's any way to avoid using an electric fuel pump, I'd choose an original mechanical pump. The only reason I'd consider an electric would be if the pump lobe on the camshaft was worn or damaged.
Jerry
