[blykins]

Not much choice in main bearings for .020" under. I'd use a King 559AM020 for the mains. Federal Mogul 8-7170CH for the rods.

If you want a performance bearing for the mains, you can also grab a set of Federal Mogul 146M20 bearings and grind the tangs off. They are Cleveland bearings, but the Cleveland shares the same main bore housing diameter as the FE; just the tangs that are different.

For a ring compressor, you'll probably have to go to an adjustable one.