After doing a couple of upgrades and a bunch of maintance I took a 4,000 mile trip. I calculated the MPG when I took the time to fill right to the top of the neck. Most of the driving was at 72-75mph from Montana, Wyoming, Colorado, Kansas, New Mexico, Arizona, Utah, and back to Montana. So there was lots of hills and flat. My cruise was not working .
16.9, 16.5, 18.1, 19.45, 17.0, 19.89, 19.34

All except the 17.0 was highway, the 17.0 inlcuded a bunch of mixed driving. I had more fill ups but did not take the time to fill to the top of the neck and the tank could have held 2-4 gallons more so I didn't calculate MPG. I think part of the lower first 3 was related to Winter Blend #2 or could be took some time for new gears and water pump and things to "break in". Truck now has 160,000 miles not too shabby at 75 mph.