Looks like I got it fixed?
The MC came with a set screw installed as stated previously. It did have SAE threads. Why...I don't know. I cleaned the threads with a tapered tap and used a brass 1/8" pipe plug. The leakage seems to have stopped. I'll watch it over the next few days to be sure. This project is a long ways from being drivable so, I've got plenty of time to get this right.
Thanks again.
