Someone tell me I ordered the right thing please

Slantsix64 said

Don’t think it’s going to work in your dart 4.5 bs is better for big bolt pattern axles. Better fit would be 15x7 4.25bs with a 255 60 tire

on a 67-69 barracuda you can fit a 275 60 15x8 with 4.25 back space small bolt pattern axles with no modifications. On a dart you will need to relocate springs etc.

Click to expand...

If that is true, just use a 1/4" billet spacer. No need to move the springs, unless you WANT to.
Thats what is nice about "too much" backspace. It can be fixed. Too little and the tire crashes into the outer fender, and that cant be fixed.
Edit: i DO agree a 15x7 would probably be a better fit. But his 15x8s are in the mail, i think .