33 12.50's on stock rim? or 15 x 8's

Getting ready to bump up from a 3" lift to a 4.5. Gonna go from 31 10.50's to 33's. Looks like the largest selection is at 12.50's. I don't think I can run those on stock 7" rims...right? (not a tire guru).

Also, if I switched to an 8" rim, what backspacing would keep it reasonably inside the fender. I've already cut the wells but don't have the extra $400 for new wide flairs.

Thanks!
Coakley

4''bs would work fine

get the 15x8's

Thanks for the help. 15 x 8's w/ 4" bs.

Looks like I'll be selling parts from a 3" BDS lift.

Later

8"s.......

4" might get them out a bit much. when i went to 4" bs i had to cut a good deal more fender. might want to consider 4.5"