There is a muffler hanger that is attached to the frame.

There is a tail-pipe hanger that attaches to the rear-most frame rail (on a pick up).

Jim Carter sells both those parts.

Chevs of the 40s sells an exhaust system but it seems expensive if it is plain steel. They sell each part separately and they sell the hangers. Also, they have the panel-body tail pipe (it is different from the pickup tail pipe).