I have heard good and bad. The only bad I have heard is that you will need to go back through them to make sure eveyrthing lines up. A friend of mine picked up a set for his 460. By the time he had them re-surfaced, the ports cleaned up, and just the heads over all gone through he could have picked up a name brand set for a few bucks more and had alot more peace of mind. There was slag in the oil return holes from a poorer casting to give you an idea. Just my .02