you need to do a lot of careful measuring , a 295 50 15 tire fits perfectly on an 8 " rim with 4" backspacing , you cannot fit anymore tire under there without moving something , the spring would need to be moved 1st , offset mounts would gain approx 1" more , then you are into notching the frame & mini tubbing the body to gain more room . The only other option is to narrow the diff & change the offset of the rim for example narrow the housing by 1" each side & change the whell offset by 1" so you still use an 8" rim but with a 3" backspace for a deeper look