Guess I am full of it then. Had an old 12v Cummins that got 22-24 day in, day out.
My '04 Dodge got about 20-21 empty and more than a few times got over 700 miles on a 34 gallon tank. Do the math. That was on a stock motor.
Currently, this truck puts out <900hp + 1650 tq. With a little squeeze it's 1150 and <2000.(dyno stops at 2000 tq, so I don't know the real number) That's at the wheels. It's run as low as 11.2 seconds in the quarter mile @124 (on squeeze). Then I hook up my 12k 35' fifth wheel and go for a drive. My last trip of 5000 miles doing a Wyo, Montana, Canada, Idaho Washington and Oregon loop I had overall mpg of 10. (Most of the miles were towing, not all obviously).
So what can your little twuck do?