Best Cruise Speed

[Chadahootchie]

I want some opinions on what everyone thinks my trucks best mpg speed would be on the the hwy. I never go over 60 mph because im turning 2000 rpms and think it would really start sucking fuel if go any faster, Im I wrong in thinking that? The truck turns about 2400 rpms at 75 mph and feels like its screaming for cruising but its not working hard i dont think. At 60 mph I get about 12 mpg.

[Fireman40]

I run 2000rpms at 70mph. I find on the highway for me at stock height and 285's that seems like natural cruise speed. If I go any faster (which I always do because I have a need for speed) the fuel mileage drops dramatically.