It is only 3/10ths of an inch shorter than a 275/60/15 and 8/10ths of an inch wider
So back space is the deciding factor
Are you making the axel a body length? Or just making the shorter side the length for both sides?
If you are doin what I mentioned second research online the full width of the rear end from disc mounting face to mounting face then the drum face to drum face on a stock 8 3/4.
Subtract the widths and divide by 2 and this will tell you how much longer the axel will be that much longer or shorter than a factory 8 3/4