Personally id go with a roots type blower, reason being is that with a blower with a boxed in carb is hard to adjust and judge and is basically a pain in the a$$, just my opinion. also you need a fuel pump and a regulater designed to overcome the pressure created by the blower. Id go with a 6-71 blower, underdriven...alot but really id build the 350 you have for the blower. Roots type superchargers arent as efficient as centrifugal types but when you are using that box around the carb its a b!tch
to adjust and set up for when the blower is boosting. Let us know how it works out for you.