I believe the exhaust is the lowest point on my '81 as well. Specifically, the driver's side at the bend upward past the spare carrier. There's a clamp right at that point that hangs down at the lowest point. It actually scrapes every once and a while going over bumps. Have to baby it over RR tracks. I remember a guy back in high school (looong time ago) who almost ripped the whole rear end off his camaro when his traction bars caught on a protruding rail.

It was ugly!
H3