Hughes heh237/242 in a 360?

FWIW.. At a steady 65 mph in flat midwestern country like where AJ dwells, I would 100% for sure get 29 mpg in my '76 Dart Lite /6 with the 4 speed OD, and 2.76 rear axle. Stock from the factory, never touched or optimized; though they did have a lean carb setup in there. No idea of the RPM's but it had to be down there like AJ's. And a '76 Dart was not exactly an aerodynamic marvel LOL.

Almost forgot: My '09 Challenger 6 speed OD manual will get 28 mpg at 65 mph in flat country..... every day of the week. Bigger engine than the Dart Lite, so more pumping losses, but the aero is a lot better.

10% or 12% more MPG from those 2 pure factory efforts would be 32 mpg and so is within reach if the engine and drivetrain are set up to be highly efficient and the aerodynamics are good. Tweak the timing for fuel MPG and so on.... certainly sounds doable. I bet if we all read up on the fuel mileage challenges held over the years, we would be impressed.