I just now expanded the picture of your engine posted above. I remember reading about your headers a couple of weeks ago.
That explains why you are removing the tube headers. I had made the assumption that it was because of header gasket leaks.
I would think a good muffler shop would have the skills to replace that bad section and reroute that tube with the needed clearances.
The guy that built your truck was a real hacker. good luck.
