TV pressure port bolt

I made a gauge to set the pressure in my transmission for the TV cable. But when I tried to take the bolt out to hook it up, the head striped off the bolt. Somebody must have used lock tight when they put it back in, I tried vice grips but they just slip off and now it's rounded with no sides. I have a 295 arc welder to heat the bolt up and maybe break it loose but I'm worried about hurting the transmission or something catching on fire if I do it that way. Is there any other ports on the transmission I can hook my gauge up to? My car is a 91 Thunder bird 5.0 HO with a 92 3.8 AOD transmission. Any advice would be appreciated.

Well if you use the welder to heat up the bolt, you'll end up welding the bolt in. So don't do that. Use a torch if you want to heat it up.

try brazing a crappy old socket to the ruined plug. to easily break red loctite you have to heat it to around 300 deg. (it has been a while since i heard the exact figure so that may not be accurate). god help you if they used that stuff. you may also want to try sharpening your vice grip's teeth with a triangular file. it makes a world of difference.