Back spacing on 15x8 rim for 69’ Dart

Looking at buying a set of centerline wheels for my 1969 dart swinger 340 4 speed and I’ve been having troubles finding a set since I guess the don’t make them anymore? Found a used set local, they’re 14x6 with 3 3/4 back spacing roughly and 15x8 with 3 3/4 back spacing roughly.... will they fit on my car? I was told 4 7/8 for the rear but just want to confirm this.... the car is completely stock....

Is it still small bolt pattern factory axles?

If so 4.5" backspacing will work. But you might fit a 245/60/15. But 235/60/15 is more realistic cause the 8" wide rim takes the tire bulged outward. And a 235/60/15 on a 15x7 with 4.25" backspacing is a safer bet.

On my 68 Dart, I have 245/60/15 on 15x7 4.25" backspacing on a factory stock small bolt axle 8.75. It barely rubs on inside and out. Has worn leaf bushings.

^^ depending on bolt pattern 4.5 to 5 inches. Five is the closest I can get without touching the spring (1/4 ") on my Duster, it has the same inside measurement as the Dart, just outside fender is different. Like guy above said 4 inch pattern is 1/4 " shorter than the 4-1/2 pattern, you can use spacers to move out a little. Watch the front edge, to tall a tire will hit.

I put stock 15x8 warlock(lil red) rims on my 69 dart with re-drilled to 4.5" bp stock axles and the springs not moved in. Do not recall tire size, but the rim itself fit pretty well.