You can get 1hp per cubic inch out of a 350 all day long and use the stock bottom end! Flat top pistons and a new cam, closed chamber heads, carb, intake, headers etc... No need for turbos for that kind of power.
But if you do want to turbo it with a blow through carb... you'll need to do some reading and research. Make the bottom end stout and don't cut corners. It can be done, but not for cheap.
Gary