I am going to put a supercharger on my 91Gt. I have a 347 Stroker on it with 9.1 compression. I am tying to decide between the Vortech S-trim that's run about 2,500dls and comes 10psi pulleyt, capable to put 20psi of boost by changing the pulley or the Powerdyne that's run about 1,900dls and comes with 9psi pulley.