Robbie, have you driven White Rim in your 80? If so, how did your fuel consumption compare? I tend to get the equivalent of about 10 MPG on average, although I prefer to do my calcs in gallons per hour. It's funny, though, my truck generally gets close to the same gal/hr regardless if it's 65MPH on the highway or intermittent 4wd-low.
"Silent enim leges inter arma." -- Cicero