1994 Ford T-Bird front tension strut

Are you referring to the lower bolt that goes through the strut's lower bracket and control arm? If so, use a sawzall to cut the bolt on both ends just inside the strut bracket, then get a new bolt and nut from the dealer.

When you tighten that nut, the car must be sitting at normal ride height. That means leaving it loose, bouncing the car on the ground, then crawling underneath to tighten the bolt, (unless it's sitting on a drive-on hoist). When you tighten that bolt, it captures and holds the rubber bushing in the lower control arm. If you do that with the suspension hanging down, it will put that bushing into a permanent twist when you lower the car to the ground. That will greatly reduce the life of the bushing.

OHHH! I'm stupid. I couldn't figure out what you were referring to. Never heard it called that before. That nut is going to be real tight and there might even be a roll pin through the threads of the rod. An impact gun is probably not going to be real effective because they work with a hammering action. Since the bar is mounted in rubber, it's going to bounce and absorb those impacts.

Try holding the bar from turning with a big pipe wrench, then use a 3/4" breaker bar and deep socket. You will be getting your exercise for the day. If you can anchor the pipe wrench solidly, an impact gun might work but be aware that nut will be real hot when it comes off.