Again, I appreciate the information. In God we trust, everybody else bring data.

I will monitor over a longer period. That will help with weather, wind, terrain, fuel, and other variables. But the 5s were a bit lower than I expected.

On both the 12.7s I owned, I picked up almost 1 mpg when I ran the overhead. Looks like I am going to learn how to get the closet floor out of a Marathon. Should be easier than my previous attempts because this engine does not have Jakes that are in the way of adjusting valves and injectors. This coach has trans retarder.

Oh yeah, I need to check to ensure the fan is not ON all the time, that will kill the mileage.