I just returned your private message. I do have a really for the 74-76 Duster, Dart sport and dart swinger now and it is adjustable to take up space of the filler panel. I'm sorting out some details of the differences in the fronts of those three models. I believe since the swinger has more point in the bumper my bracket needs to be longer. I have a fix for it.
The bolt pattern is set for a 73 Duster front.
I'd like to get a 74-76 dart and duster bumper shell so I can make a plate to fit the factory holes.