Joe Suchy is the early B body expert that I see mentioned a lot. I've never talked to him and he doesn't appear to have a website, but he posts over on the For B Body only forum.

If you end up making some parts I wouldn't use a CNC milling machine. Just draw up the parts and have them cut on a laser. I make custom alternator brackets all the time from laser cut 0.188 thick steel. Fairly cheap and fast process. Here is a new low mount 90 amp alternator kit that I just built for my Duster.