Needs to be 4 1/2" backspace to fit 245/50/15 or 225/50/15 tires. And I don't think anyone makes a 245/50/15 anymore.
Other than that you'd have to try a 60 series tire that would be too narrow for 8" wide rim. Like maybe a 205.
I've fit 245/50/15 with 15x8 4 1/2" backspace on my 68 Dart. And it was close. Also ran 225/60/15 with 15x7 4.25" backspace with poly strut bushings and 3 defy positive caster that pushed the wheel back a little.