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.