Mileage for 8.1

[Jim Henington]

Hey guys, new to the site. Just wondering what kind of mileage you guys are getting on your 8.1's. My 03 2500hd w allison is stock and I am getting 9.8 mpg. I tow a 8000 lb 5th wheel and have all the power I need and the mileage seen to be about the same towing or not.

[Colorado Kid]

My father in law has a 2003 2500HD with teh 8.1L. Empty on the highway 13-13.5 mpg. Towing the 5th wheel (29' single slide Hitchhiker) 10 mpg. Around town he uses a car, but I think 10 mpg would be a good guess.