I had a 96 3500 2WD reg cab, 454/4L80E/4.10's that I got 13 with on the highway empty, and usually 11 daily with. I was pretty happy about that. That is one reason why I thought this 6.0l should be doing better than it is. It is a K2500, with 4L80E and 3.73's, and of course it does have 180K on the clock too, but it takes no oil on a 5000 mi. oil change, and still runs pretty good.
