You would really need to build a strong bottom end and keep your compression ratio lower 8 - 8.5:1 tops. A steel Crank designed for supercharging with a special key way, rods, and forged pistons are a must. Your cam exhaust duration should also be slightly longer.... I would use a gear drive system also. Realistically If you are going to spend the money on a supercharger, pull the engine and do it right especially since you don't know what it has inside it. Good luck with it!