What I remember most about my '77 F250 with a 460 was that it got a consistent 8-10 mpg. Didn't matter if it was empty, carrying a 9.5' camper, or towing a 5th wheel. Uphill, downhill, or off a cliff, mileage was the same.
Great truck. Hated to see it go when I bought my current '95 Ram 2500 V10.