Yes, there is a $8,000.00 difference between the two identical trucks. They were used by a flat bed company.

driver can easily make 1 mpg difference. And as Gman mentioned, so can the terrain.

The few folks that I know that have had exposure to them have nothing good to say about the C-13's since the first round of emissions came out. Just thought I'd throw that in :lol:

That could be the problem right there. Pen and paper only. Dash readouts will always be wrong, but they will be consistantly wrong. You cannot compare two trucks via dash readout, but you can compare the same truck one run to the next. You can tell if one run you got better fuel mileage, but that's about it.

Perhaps the c13 is not the best, no worse than a m11 right?

Anyways I hand calculated and i got 10.9 first tank and 11.2 second tank bobtailing back from AZ to NC. Pretty good, I had the cruise set at 66-67 the whole time.

heck thats not much worse than my chevy silverado with the 454....

Yea the rig has some legs on her, at 66-67mph it was turning 1400 rpm. It is a real light weight truck (15,900) and is a flat top sleeper (less to go through the wind I suppose).