Sean Hyland is waaayyyy too expensive!! Are you talking 350-400 at the wheels? If so, you're talking boring, stroking, porting and upgrading everything you can get your hands on!! That still might not get you in the ball park. Getting 420hp out of 281 cubic inches is the minimum, that you'll need. Supercharging is the easiest route...or so it seems. You could do some high compression, high revving nitrous setup too maybe. All of which will cost you more than necessary if you use Sean Hyland products.