It's doubtful you'll make 250 with the SC, especially since this SC does not have an easy way to intercool it. Also, max boost is around 12 psi with a 2.4" pulley and is way beyond the efficiency threshold. The SC takes about 25 hp to build 12 psi at 6500 rpm--that's a lot. There are some centrifugal chargers around that may work better for what you want. For that kind of HP, you should think about turboing it.