Just my two cents, but if you're building a 1000hp car, that means some serious money on engine, a tranny to back up a 1000hp, a suspension that will hook that kind of power to the earth, and a car to hold it all together. (Tubbed, tubed, etc...) And you're asking about using a junkyard casting, rebuilt mind you, but still a junkyard piece. Figure, what, $50,000 to do it all yourself, quarter mill for someone to do it for you the price a Dana is a drop in the bucket to keep the power to the wheels without launching little bits of metal at the safety safari and the crowd. 'Cause remember, it's not just about going fast, it's also about going fast safely. And exploding rears can have a devastating effect on how a car moves...