If you have the carburetor box, I'd go that route. The Paxton set up was an option on the 66 Shelby. I had that setup on a 66 Hi-Po Mustang. I think it might have had 6 pounds of boost, maybe 8 pounds. One problem I had was with the fuel pump. Don't remember whether it was on the Mustang or a 57 Studebaker Golden Hawk I had. The Hawk came stock with a McCullough supercharger. They were later bought out by Paxton. Anyway, I had to run a pressure line to the pump because when the supercharger reached a higher pressure than the fuel pump it would shut down the fuel flow. I only bring that up because it was something that took me awhile to figure out.
If you want to go without the carb box, I'd google info on what you have to do to the carb to be blow through. I know the Studebaker Avante didn't use the box with a supercharger.
You'll notice quite an improvement in torque and all around performance.