MPG is very important, especially if you've been to the gas station lately... Ha! However, we want it to perform (as in have more zip) a little better as well.
I would be inclined to either change rockers to a higher ratio or swap the cam to a short duration high lift cam. 107 or 108 LCA for overall performance 210 to 215° 0.050 lift duration, 256 to 264 seat timing and 0.450 lift.
For that brick you need high torque at your cruise RPM which probably close to 2000.