I have searched and the consensus is that a 275/60/15 is biggest tire that will fit on my 68 with a 4.5 inch backspace. I have a 12 bolt from a 67 that I will be using. Since the 67 rear is narrower than the 68 rear, can I fit a bigger tire with a different backspace? I am wondering if I can fit a 295/50/15. If so what backspace? My current setup seems to have much more room inside of tire than on the oustide. If someone has done this, or knows that it can be done, please let me know.
Thanx guys
Bill

I have searched and the consensus is that a 275/60/15 is biggest tire that will fit on my 68 with a 4.5 inch backspace. I have a 12 bolt from a 67 that I will be using. Since the 67 rear is narrower than the 68 rear, can I fit a bigger tire with a different backspace? I am wondering if I can fit a 295/50/15. If so what backspace? My current setup seems to have much more room inside of tire than on the oustide. If someone has done this, or knows that it can be done, please let me know.
Thanx guys
Bill

I believe the biggest wheel/tire combination that can be safely stuffed in a 68-72 without body/frame modification is a 295/50 tire on a 15X10 wheel with 5.5" bs. From what I've read here at TC this is the max without causing clearance issues.

The problem isn't the rear-end width, it's the size of the wheel house. If you use a rear-end that has a width other than stock you need to adjust the wheel back space.

Correct. I know that a 8 inch wheel with 4.5 backspace will fit a 275/60/15 and a 10 inch wheel with 5.5 inch backspace will fit the 295/50/15. (may have fold the lip) This is with the factory rear end. But I was just hoping that someone here had done this with the shorter rear end and could tell me from experience what the backspace would be.
Thanks for the reply.
Bill

I think the shorter rear end gets you around 1/2" more on each side. You will still be able to use a 15x10 with 5.5" BS, there's plenty of room on the inside. You can't use anymore BS because the rim will rub the shock mount. If you run a 17" or bigger wheel you can easily fit a 315 in there with around 6" or 6.5" BS.

Thank you, I appreciate your reply.
Bill