Yesterday was the first time out since I re installed the factory engine. With the same 6.5 to 7 lbs of boost that the 6 liter was running 12.6 at 105 the 5.3 went a best of 13.35 at 100. This was in quite a bit worse weather, too. The 6.0 routinely runs 7.9x to 8.0x in the 1/8th and the 5.3 is going 8.4x The 6.0 is definitely a stronger motor and I can't wait to get it back in there. Oh yeah, I won the 13.00 to 13.99 class at the Sport Truck Shootout in Bowling Green (albeit there were only 4 trucks in that class)