The 264/70/17 would not be a good choice, for a few reasons. One is that the tire is simply too wide for the stock wheels. They really need at least an 8" wheel for correct fitment and sidewall support. The second is that you really need a tube type tire for your application, which the modern radials are not designed to be run with tubes. Those tires also may not be the proper load range, as they do come in both a P rated (1/2 tons) and LT E range (3/4 and 1 ton)ratings.
I would very leery of buying used, as you don't really know what the tires have been through.
The tires from Coker would be the right fitment, make sure you get new tubes and flaps to go with them.
