Adjustable Mirror HELP

I may have to fabricate something to make it work
Actually no you wouldn't unless you just want to. Where that cable is mounted in plastic there is a thin tempered steel piece that goes behind it.
If you found a right remote mirror in something along the lines of 87 Fifth Ave.. thats controller was mounted in dash plastic near the ash tray, thus the piece you need is in there.
When I put a right remote mirror in my 67, I mounted that controller in a second ignition switch bezel. Since that bezel has a larger hole I used the piece from a Gran Fury behind it.
Just trying to help.