They is a large difference in the way the newer truck will pull verse the old. I went from an 02 with the 6.0,3:73 gears and 4 speed to the newer 09 6.0, 3:73 and 6 speeds. Pulling my current setup and happy. The engine really has improved with the bump in HP and Tq, plus that 6 speed really icing on the cake. Now I pull in 5th gear OD in Florida, north of here I'm in 4th gear. 3rd in steep grades but I maintain speed easily. I went also with the Blackbear tune and really like it. I lost some of the Tq management and the truck feels overall lighter on its feet. Mpgs have stepped up about 1-2 and some times more when in town. Power delivery is much quicker now and I am pretty sure GM have detuned this engine from the factory. I'm sure it's for service life, but I don't dog it and use the towing only tune for towing only. Otherwise I leave the 89 tune on it for everyday driving. Even if u don't tune it, u will like this new combo. payload on my truck is 2997lbs, which I'm under that with my current setup. Am I happy with it? Yes for sure. The newer gas engines with more gearing and reliability make it harder for me to go to diesels.
