what metal work is required to convert a Mauser action set up for the original 8 x 57 cartridge so that it can fire the 9.3 x 64 cartridge.

I would imagine the magazine.
How about the follower, the bolt face, the feed ramp, the extractor, and the ejector?

depending on your box you might need to lengthen it. If so that requires feed ramp as well. Bolt face and extractor. Ejector should be fine. Follower and rails??