rationull: in my recent research for what it may/not be worth, it seems like fuel economy unloaded is near the same for all the gas 3/4 ton trucks- 15mpg. so why not get an 8.1L since the intended use of the truck is to tow and it has an allison trans. And if anything you might get a better deal on an 8.1 because nobody wants them because of perceived fuel economy so they don't sell as quick as a 6.0L.
2007 was the last year that had an 8.1L.
2005 most likely had 5-speed allison, 2006/7 had a 6-speed.
2007 was the last year that had an 8.1L.
2005 most likely had 5-speed allison, 2006/7 had a 6-speed.