Stock wheel off set

The Dart came with 4½" wide wheels. The best you can get on these and get decent wear is 185/70-14. The Dart Sport 340 came with 5½" wide wheels. IIRC the backspace on these wheels is 4¼". The biggest tire recommended for a 14x5½ is a 215/70-14.

A 15x7 wheel with 4¼" offset works well up to about a 225/60-15 tire. I have this spec wheel on both the Dart (205/60-15) and the Demon (235/60-15). No problems at all with the Dart and tire clearance. I re-hung the fenders on the Demon twice before I got the front tires free of the fender opening when turning on bumpy streets. FWIW, I tried 255/60-15s on the car. On the front it was hopeless (BBP disk brakes) and they were within ¼" of the fender and spring on the rear.

Sorry. I haven't tried out a 17" wheel combination, yet. Too old school.