Are you running the stock rims?? If so, look for a set of 16x8s from about 83 up Chevys. I dont know when the transition was, but I know our 81 still had 16.5s on it. Also look at the 3/4 ton Fords and Dodges if you are just going with a stock type wheel. I have learned that the older Ford rims will fit Chevy, but Chevy will not fit Ford because the center hole is smaller on the Chevy wheel. 2 of the wheels on our 81 were Ford rims, and the secnter caps fit no problem. I have also seen Dodge wheels from 90's Dodge trucks that fit our trucks as well, just have to do something different with the center cap. Almost all aftermarket 8 lug wheels will fit because they make them with the larger center hole so they can be universal.Maybe you can find a set of wagon wheels, blastem, paint'em and be done with it.
I would go with the 16's because that would be alot easier to find, unless you go aftermarket, plus tires are cheaper.