I don't have any answers to your questions but, I have other ideas for boost. I was doing some research on superchargers and came across the April 2000 issue of Street Trucks Magazine featuring a 1989 Mazda B2200 with a Camden 5 inch SuperCharger. It was also fitted with a Weber Carburetor, Pacesetter Header and, custom exhaust system featuring a Flowmaster Muffler bringing the peak horsepower up to an impressive 218 at 6,700 rpm and peak torque of 231 ft. lb. at 6,000 rpm.
Here is the web site for more info