I had a 275-60x15 tire on a OEM 15x7 steelie with 4.25 backspace. Car is a '67 Belvedere. The fender lips were rolled up when I bought the car. Still the fit was close. When installing, the car had to be jacked up so the rear axle hung down to give enough opening to get the tire in the wheelwell, it was a real pain.
I took them off, not because they were too big for the car, but because the 275 tire is really too big for a 7" wide rim. I mounted the tire on a 8" Rallye but never tried to fit it on the Belvedere. The 275 tire on a 8" rim may have squeezed in there but what I'm going to put back on it is a 255 on the same 7" rim.

Here's the tires on the Belvedere before removal. Front tires are 245-60.

After taking them off, this is what I put them on. An Aspen has plenty of room for a 275-60x15 in a 15x8" wheel on the rear and 245-60x15 on 15x7" on the front.