My guess is it’s probably almost 80% due to the 3.73 rear. I just did a round trip to LA from San Jose in my warmed over 273 Commando with a 3.23. Took it easy on the way down on 101, kept up with traffic on the 5 (meaning 80) on the way back, averaged 12.5mpg. Give me a 3.73 and 6mpg seems plausible… I would probably get a little better because my primaries are way smaller. But I don’t see your setup getting better than 8, realistically. You make your choices and live with the consequences.
