Instead of building your own, why not adapt something from the junkyard?

Last Saturdays local Harley/Hot Rod show had a slant six Dart with an Eaton blower from a T-Bird - I think, not sure, but Ford did run a small Eaton blower on one of their cars.
The owner reported 8# boost which sounds reasonable to me considering the Slant sixes are 170 or 225 CID.

The blower adaptation was a very simple deal on the Slant six and wouldn't be too much more difficult for a V-8.

Setting up two Eatons side by side at an angle similar to the old Romeo Palamides dragster would be a great setup on a V8 and you could underdrive the blowers slightly so as to keep the temperature down on the intake air.