I know you can get a 10" wide wheel in there with up to 5" of back space, however, tire choice and section width of that tire becomes critical. I also know you can fit a 295/50 tire in there. Again, the section width is the sizing factor and wheel back space selection becomes critical. I don't know if you could fit a 295 on a 10" rim together in there. Logically it is possible, but it would probably require some odd back space dimension that is not offered off the shelf. A 9.5 width with up to 4.5 of back space would be no problem. You might be able to squeeze a 295 in there on that rim size. A 275 on an 8" rim fits without any trouble at all.
I have 295s on an 8" rim under my Challenger. They fit fine and look like an old trans am racer, but isn't the best combo of wheel and tire as I have to run the tires around 22-24 pounds of air to get full tread contact.