Fuel Mileage on your Hemi swap?

One swap I did was an 6.4 cammed/5.7 Eagle in a 74 Challenger. Aluminum case O.D. 833 with 3.23 gears. Owner reported back with aprox. 22 mpg. That one ran really well, but, could benefit from a tune for the cam. Another swap I did for a guy was an Eagle 5.7 with 545RFE in a 62 D-100 shorty. That one also has the 6.4 cam with the 6.4 truck intake/injectors, 3.55 gear, and headers. this one was fully tuned by a pro. Owner has reported aprox. 25 mpg.