Lets make the best real world *MPG* THREAD EVER !!
1994 Ram 2500 4x2 5.9, auto 354 in rear 28 mpg hwy 25 towing car on open trailer. In 1994 diesel was cheap. That 12 valve ran well and you did not even know anything was back there.
Sweet spot was 68 mph for very best mileage. Got 30 with A/C blowing cold as ice on night trips plenty of times.
Still would not matter today with them numbers as,would be way cheaper than a few truck