This can be narrowed down fairly easily. Without knowing what you're doing axle and brake wise, I'm going to take it you're still running the original 6 x 5.5 bolt pattern. That will narrow down what you need quite a bit. You won't find any passenger wheels that will work, nor will any Ford or Chrysler wheels, as they are all 5 lug (5 x 4.75 on Chevrolet, 5x5 on Ford truck, 5x4.5 on Ford and Chrysler cars). From GM trucks, any 6 lug up to '70 on 2wd trucks, and '87 for 4x4 pickups, '91 for 4x4 Blazer and Suburban, will work. Some years of Japanese truck 6 lug will work, too, mainly Toyota, Isuzu, Mazda, and Nissan. Mitsubishi uses a smaller 6 lug, those will not work. You will have to use some caution with the Japanese wheels, they run a positive offset and backspace, and can rub the drag link on a hard left turn.
Now on to the tire size. You can find the suggested rim width specs on the tire manufacturers websites, they usually give a minimum and maximum widths, as well as the preferred widths. In the case of the tire size you have listed, a 7 to 8 inch wheels what you will need. With the stock wheels, which should either be a 5 or 5.5 inch, a 225/75/15 would be pushing the limits of what can be safely used.
