I'm running an outfront grocery getter with longer rods short block, stx67, grimmspeed topmount/intake/crosspipe/uppipe, cobb ebc, turbo back exhaust. My auto was rebuilt by IPT with an upgraded torque converter. 2" lift with upsized tires. With stock injectors and 91 I put down 315/350 on a mustang. The stock injectors are maxed out and run lean if I push it. I will be upgrading to FI1000's and getting a retune in a couple few months. I'm hoping I break 350hp. I bet the 6 speed will get you closer to 400. Past that, I think you'll need to consider water/meth injection in order to hit 500.