Does anyone know if a 245-60-15 tire will fit on the front of a 67 GTX without anyone rubbing/clearance issues? They would be mounted on a standard 15x7 Magnum 500 which if I remember correctly has 4 1/4" backspacing. I would also like to know if a 275-60-15 would fit on the rear mounted on a 15x7 wheel. I'm pretty sure it wouldn't fit on an 8" wide wheel.

here is 245s and 255s on stock chrysler 7in rims.275s were too wide for tried them on a 7inch rim and they were tight and didnt look right because the tire was pulled in too much on the rim(7inch rim)

Usually ran 2157015 or 2257015 up front.
Besides,with over 2 inches O.D. difference between the 2456015/2756015's, that would give the car too much of a front rake and more nose down--that is if you are after that look.

15x7 are a tight fit for the 275's tires and look like a bulging ballon.
The wheel vintiques 15X7 and 15x8 has 4.5" backspace
Hope this helps
Not much room out back for a 275...2556015 is best on a 15x7 rim

275s

If you go with the 4.5" BS, watch the clearance at the upper control arm ball joint area: using a 14x7 Magnum, clip-on weights interfered on my car. Using the adhesive weights on the rim barrel solved the problem. Wasn't an issue with 15 x 8 Ramcharger rims.

I had 245-275x60 on late '70s 15x7 w/4.25 bs steelies.
Axle was '69 4.10 Dana, 5/8" wider than the '67 4.88 Dana it came with.
275x60 fit but was very tight, had to deflate air and remove shocks to install. Another reason not to use a 275-60 it is not recommended for 7" wheel, you need a 8", I doubt it would fit.
The 245-60 fit fine on the front.

I'm going back with my original '67 Dana after I install a thin 4.10 gear. Changes will be, a 15x7 4.25 bs wheel and a 255-60 or 255-70 rear, and American Racing TT 15x6 with a 215-75 front.

I think the question was 245's on the front.... I have 245/60-15 on the front of a 67 Charger with an 8" wheel. Slight rub on the inside frame area.