Well, in the big picture my mechanical going over of my new-to-me '88 RT has been going very well -- engine back in the frame, jugs/heads back on/etc. with no significant issues, and I'm in the home stretch.
I decided to fill the fluids tonight so that I can close up the tranny and put the carbs back in place -- the last step before start-up and initial break-in of the freshly dual-plugged/9.5:1 motor.
Ah, the best laid plans, etc. ...
I started to remove the final drive *fill* plug (I'd never touched it before this), and instantly felt that sickly, kinda "thick" feeling you get when you know that the threads are *already* stripped. The plug was basically being held in place by friction from the remains/debris of the old threads. It would rotate, but not back out of the hole (I ended up rotating it while applying pressure with a pick behind the plug head to get it to gradually walk out of the hole).
Once the plug was out, I used the pick to gingerly remove ~6 3/4 circle rings of aluminum thread shards. Fortunately, the last thread in the hole is intact, and appears to have acted as a "wall" to prevent any of the shards from dropping into the drive housing (nonetheless, I will be checking out the internals for debris).
So, how would you approach the repair? I haven't checked a fiche yet, but the plug appears to be 8x1.00.
Tap for a 10mm plug?
JB Weld the plug in place and fill the FD via the breather cap in the future? (just kidding --I want to fix it "right")
Thanks for your suggestions!