[patf11]

Originally Posted by Cashburn

If you maintain highway, 30 is realistic.

Here's a log, mostly 20s, but an aftermarket tune and 3.91 rear ratio (and things like the Rocky Mountains to drive over):

# Date Miles Gal. MPG Price City % Notes
21 9/25/12 166.0 10.64 15.6 4.069 65%
20 9/7/12 174.0 12.39 14.0 4.099 30%
19 8/28/12 206.0 11.82 4.199 45%
18 8/25/12 211.0 9.62 4.159 20%
17 8/25/12 231.0 10.55 21.9 3.799 5%
16 8/24/12 296.0 13.15 22.5 3.979 20%
15 8/24/12 159.0 12.67 3.689 20%
14 8/22/12 188.0 5.00 3.940 35%
13 8/21/12 241.0 10.78 22.4 3.749 25%
12 8/21/12 145.0 7.27 20.0 3.759 10%
11 8/20/12 200.0 9.33 21.4 3.899 30%
10 8/20/12 211.0 11.04 19.1 3.880 10%
9 8/19/12 118.0 10.14 3.709 10%
8 8/19/12 259.0 7.76 3.799 10%
7 8/19/12 257.0 10.88 23.6 4.099 40%
6 8/18/12 76.0 12.25 4.069 65%
5 8/17/12 267.0 3.95 4.679 90%
4 8/16/12 304.0 14.91 20.4 4.099 10%
3 8/16/12 185.0 8.21 22.5 3.979 20%
2 8/15/12 285.0 12.35 23.1 3.839 10%
1 8/15/12 13.35 4.119 20%

I would be willing to bet the highway mpg was achieved at 80+ MPH