Hello all,
Some of us have AC Delco high amp output alternators. And, that same "some of us" have the problem of the alternator casing lower bolt hole being slightly larger than 12mm AND the width of that alternator casing mount being too narrow requiring a PIA shim so that it fits snug in the Mercedes alternator mount.
One solution is milling a brass collared sleeve bushing. Then, bore out the hole on the AC Delco alt body, insert new sleeve.
If you have an AC Delco alternator and know what I'm talking about and would like one of these bushings yourself, let me know, I'm about to order a few.