Regular gasoline contains 44.4 megajoules/kg. They say they used 2 pounds of fuel (up a 30 degree incline at 65mph for an hour), which is 0.907 kilograms, or 40.271 megajoules of energy.
65MPH for one hour is 65 miles, up an incline of 30 degrees is 32.5 miles up in the air, or 52300 meters. E=MGH, therefore, if we assume the van weighed 1300kg (2866 pounds), that would require 667 megajoules.
In fact, ignoring air resistance, rolling resistance, and drivetrain losses, and assuming a 100% efficient engine, for their statements to be true, the van must have weighed a whopping 78.5 kg (173 pounds). Considering a 318 weighs in the vicinity of 500-600 pounds, the van that they chose must have weighed around -400.
Sounds a little unrealistic to me.
edit: 667 megajoules, not kilojoules, sorry.