[rdorman]

I have a 351C set up almost exactly the same as yours (manifold, Ford cam of similar specs 6250-A341, etc) less the supercharger and averaged 15.25 MPG at 80MPH with a 3.75 FINAL drive on a 2000 mile trip. Engine speed at 80 is about 3900. Wonder why your gas mileage is so much lower? I know that the double pumpers are usually a bit rich out of the box.

Vacuum, 16 inches at idle.