73 Duster front tires.

What is the backspacing on the rims?

I doubt there's any way to make a set of 15x9's fit the front of one of these cars that doesn't involve radius cutting the front fenders and adding flares. You need close to 6" of backspace to make a 9" wide rim fit inside the fender with any decent size tire, and you'd run into interference between the rim and the suspension before you even hit 5" of backspace.

Generally speaking, even a 15x8 is a poor choice for the front rims. In order to fit a tire wide enough to need a 15x8 you'd need 5" of backspace, and a 15" rim just doesn't fit at that point.

235/60/15's are not an easy tire to fit up front. They're 26" tall, and that kind of height for a tire of that width usually causes interference issues at the lower front corner when turning.

15x7's with 4.5" of backspace would be the way to get a set of 235/60/15's up front. They'd still be tight on the fenders. 225/60/15's work on most cars with a 15x7" and 4.25" of backspace, even those were close on my '74 Duster with 73+ disks.