I have a 2011 Cheyenne/Ultra and straight out of the mold right off the trailer with a 509 750 HP motor with an AB stainless impeller ran a 11.90. After a year of just running it with NO adjustments other than a wedge we have moved the motor forward from 20" to 28" installed a diverter, stuffer, back cut shoe and added some fuzzy dice to the dash. My question is how much can possibly be gained by doing such using the same power? 1-2 seconds??