My 96 SuperCab Longbed HevyDuty F250 460 EFI w/ 4.10's gets around 11 MPG on average, using only 85 octane in Colorado.... Only mod is a drop in K&N filter.

I don't know what the newer ones get, but I demo'd an '89 454 with TBI for a couple of days and it was only getting around 9 MPG...

Comparing Apples to Oranges here... Take it for what it's worth.