Jim, I have the hanger you show on mine, but further back on the frame rail is another set of cut off brackets that I am curious about. Probably 15" further back. Looks like about 1/4" plates on both sides of the frame rail that have been torched off some years ago.
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible