I get between 16-18 on highway and 10-14 around town. I would imagine that the 1028 would get only a fraction or so less due to the extra weight and tires. I religiously only drive 50 to 55 with my truck on the highway. It's debateable if you can go faster. Some say yes, others no. With my tach, 55 is about 2750-2800 rpms which is at the top of the suggested rpm band for the 6.2L. I've heard guys on other forums say you can take it to the gov. and ride it like that all day. I tend to think not. Most guys like to see the truck at 2500 which is about 45-50mph. At any rate higher speeds mpg suffers, and it was always more important to me to get home rather than get home 10 minutes quicker. 55 kinda sucks on the real long trips, Adds about an hour to my trips up to Wells NY, but most people passing you at least in my expierence think the trucks are cool so its a worth while trade off.
