i seen this is MM&FF this month issue, they took a bone stock 01' GT with a cat-back and headers and put a new kenny bell twin screw super charger and made over 500hp on the ground with stock internals. i think it was running like 15psi. but anyways they dynoed it before hand and got like 247RWHP @ around 4,500. when they added the twin screw at 6psi it put down 357 then 9psi 398, 11psi 430, 15psi 511