any body building a mopar for max mpg?

I'm building my 318 Duster for good mileage and power. MSD-type CD ignition helps a lot (especially for old low-comp open-chamber engines). I'm also going to 800 cfm ThermoQuad on factory iron 360 manifold, 2.5" dual exhaust with X-pipe off stock manifolds, and Crane H-260 cam. Car has 2.76's stock, so those will help with mileage.