Super charger takes horsepower to make horsepower. Turbo charging is free horsepower. I am in the process of turbo charging my 82 3.0 sc and thanx to some used parts from pelican board members it will be completed under $2500.00 with used intercooler, new turbo and new msd box. But i dont think its going to reach your goal of 300-350 hp. I am hoping for 225-240 hp to the wheels at .5 bar (roughly 7 psi) boost.
Good luck with your build, post some pics and if you learn anything i need to know please pass it along
