Heres a cute little blower on a well built small block. If you want big block power without all the weight and size of a big block, then an engine like this would do the trick. With 5 -6 psi. of boost, this little guy can easily hash-out 450 - 500HP (and at least that much in torque) with the simplicity of a single carb, and still have a smooth idle and plenty of vacuum for running accessories, plus it'll fit under most mid size car and truck hoods! Now THAT's a great little set-up!
Something like this would run you in the neighborhood of $13,000 or so. Of course as the options go up, so does the price. Nothing with good quality is cheap or free these days.