Should be doable without all the "theory". Main thing will be the carb, exhaust and ignition. Assuming both have a 2.45 rear, the first is a a good ignition. I run Taylor Spiro Core wires, platinum spark plugs, new cap, and new rotor. Convert to Chrysler electronic if you have any ignition problems. Play with timing to run as much advanced as the engine will allow. The best carbs for mpg are the 73?-75? BBD Carter with the adjustable rod hanger, Thermo-Quad, and the Quadra-Jet (318 and 360 trucks and vans). We could get 25 mpg with a factory 75 Cordoba 318 BBD and have gotten the same or better with the Thermo-quad. A good Quadra-Jet should be close to the Thermo-Quad. Use a Performance or Vacuum gage.
