Just thought I'd share this for anyone with a 78-81 Gbody wanting to get newer rotors to use metric lugs (If you had swapped in a newer rear end) you will need to buy '82 outer wheel bearings. I have a '86 GN rear end in the elky and ended up chewing up a rotor this morning so I swapped in newer rotors to have a matching set of lugs. The inner wheel bearings are the same, but the outers are just a little smaller. Hope this helps someone out.