Pretty much any GM 8-lug wheel will fit pretty much any GM 8-lug axle. The problem comes when you try swapping a GM wheel to something else. Dodge and Ford use larger hub diameters. I have some 19.5" dually wheels from a box truck I wanted to put on my Ram, but I would have had to enlarge the center hole. Now that the Ram is retired, I'll just save the wheels.
You also have to watch out for the newer Ford (late 90's+) axles- they changed to an oddball metric pattern that doesn't fit anything else. They are close, but not close enough to be safe (if you could even get the wheel over the lugs). Newer Fords are also hub-centric, meaning that they use the hub itself to center the wheel, so the wheels must be a very close fit. GM and Dodge use tapered lug nuts to do the actual centering of the wheel, while many Ford lug nuts just have a flat washer built in. The exception are duallys, which all use the hub.
Jim
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