Dr No[Moderator Omega - Wristscan]
37505
I'd use a Feather Duster . . .

. . . as a starting point. A standard Duster with a 198 c i slant six, overdrive 4-speed, tall rear end gears. Aluminum substituting for steel over parts of the body. 30 mpg overall - in 1976!
Back it up with a Passon 5-speed and 4:30 gears into an 8.75" rear end, irs, discs all the way around, and suitable 16" - 17" wheels . . . Dr No wouldn't say no to that beast.