Yeah I heard that too. But after I researched it, I came to believe that the run-out issues were actually machining issues. It seems the equipment (now don't hang me) of the 60s and 70s supposedly had a hard time with parallelism.I can't speak to that. In 99 I happened to be working in a shop with a more modern machine, so I machined my own KH rotors,taking multiple very thin, slow cuts.(they didn't need much). It seems to have worked cuz they are still on the car, have never been retouched, and still stop smoothly.(unlike my pos '06 LaCrosse) I did, however buy a donor car with KHers for spare parts. They are still on the shelf, 17 years later.