seeing as my supra's off the road at the moment, my current daily driver is my other car (well, the other _Driving_ car - there's 3 more out the back in bits), which is a 91 f250 ex-ambulance....
ford decided that these babies needed to be fitted with a 351W, c6 (3 speed, 1:1 top) and a 4.11 rear end.... combine that with a not overly aerodynamic body style (slightly more aerodynamic than the big box type ones that were used in the US) and I'm getting around 9 miles to the gallon on a good day....
a few weeks back, when prices were at their highest, i was able to put A$150 (around US$125 at the time, more like US$100 now) in, and still not fill the tanks (2x 72 litre tanks, from memory about 38 gallons?) - that would last me just over a week....