You don't need to get wacky with it to get 300hp out of a small block, stick with the tried and true stuff. Cams, light port work on the heads, exhaust, would get you knocking on the door of that 300 hp mark. 350 hp isn't too much further than that, but I think you start trading drivability off if you start going past that 1hp per cube wall. A blower might get you there faster, there have been alot blower kits that have came out, and the info is avalible. Just check it out.
Twiztid