The location of the bellcrank on the subframe is actually pretty easy. It will only go into one location. It's on the inside of the driver's side. When you get the parts, I'm sure someone here could post a picture of where it goes, if they don't when I get back to the states I'll see what I can come up with. Good luck with the cable replacement.
Restoring a 1968 400 4spd, numbers matching Firebird Coupe, Verdoro Green. Larry My old 68. Wish I had her back.