OK, rivets it is with hi-temp JB Weld slathered in between for vibration / filling. 1mm stainless sheet for the patch.
Next, I sourced a rebuilt externally regulated alternator (direct replacement). Car runs, shows 14V at the lighter, but the J. Bell quad-gauge LED alternator light is on full blast It was not before replacing the alternator.
Re-opened and checked the wiring (I thought the black wire may have pulled off of the terminal in all the to-ing and fro-ing), but all is in place. The only thing maybe to do differently is separate the 3 browns from the 1 brown on the two different B- studs.
Ideas?