If your wheels have countersunk holes for beveled lug nuts than they do not need the wheel to fit tight on the hub.
If the wheel has no beveled holes than it has to fit tight on the hub.
It may be that some original wheels fit both ways?
As to the Chevy ford and dodge thing, I have used ford wheels on my Chevy just fine. Ford and Chevy wheels will not fit over all dodge hubs. So Dodge has the largest hole, and can't always use other wheels on a dodge, chevy and ford are smaller, in no perticular order.
