I used to have an intermittent stalling from my 63 vehicle with 4GC, shifter on column, and AUTOMATIC dual path transmission. It occurred in all kinds of nerving situations: intersection, making a turn, freeway, etc. The nipple on the neutral switch broken off made it possible to turn the car on while it was still moving. So, if I was on the highway in the fast lane and it stalled out, I didn't put myself in danger of pulling over to start it again. I started it up in motion. I drove the car for many years this way and didn't know it wasn't supposed to do that. I eventually replaced the neutral switch and guess what, the car stalled on me on the road, and here comes "pedal to the metal" coming straight for me and slams on his breaks. I veered away and rolled to stop to avoid getting side swiped. So, even though I regret replacing the switch, it pushed me to investigate the stalling and fixed that.
If you don't mind waiting, I can look and see if I have my old part to see if I can make a replacement broken part. Also, you could make the broken piece with PC11 Marine Epoxy. To make a mold of the piece, drill a hole in wood the diameter of the broken piece to the same depth. To make it easy to remove from wood, put Vaseline in the hole you made in the wood. Give it a goop head so you have something to grab after its cured. Grind the head of PC11 stud you made and epoxy it to the switch. Don't forget to prep the switch for good bond.
