68 barracuda tire size question

Most oem rims are a zero offset. My Kidney slot mags are close to a Zero, but a little offset ,IDK.
So the backspace would be 3.25 on the 5.5 steelies. And maybe as much as 4.0 on the aluminum slots, but I think it was less, like maybe 3.75. Ima guessing. The've been on there since 99. No,not with the same tires,lol.

OP; But seriously, If those Redlines are not radials, they are only good for keeping the chassis off the ground, and not very well at that. I'm hoping this is for restoration purposes, cuz I wouldn't spend the money to mount them, if I had them given to me. And I hope you don't think me an a$$ for saying so, but bias plys and polyglass were junk when brand new, even tho they mighta bin the best in their day.Now I'm not knocking certain biasply slicks here, I'm talking about passenger car tires.
Post #4 edited.