Originally Posted by hightech

There are two tuners that can get 400HP @ the wheels without going into the engine. One is in Tennessee and the other is in Texas. The tuner in Tennessee can get a better torque curve with his tune and had the bolt on record for the LS1 until the tuner in Texas beat them by about 2 HP...but again the fat torque curve more than makes up for it. So yes it can be done but requires extensive tuning and know how to make it happen. There are probably more tuners capable of achieving these numbers as well.