What engine would you build for a Ramcharger?

Here's my take on mileage.
It takes a certain amount of power to cruise at a certain speed, and it don't matter how many cubes you got(within reason) if you get the Afr set right, any engine will get it done.
Now the getting to cruise rpm, and more specifically, what the cruise rpm is, is where the fuel gets used.
So with a small engine, it is easily possible to spend a lotta time and use a lotta throttle to get to that cruise rpm, whereas a bigger engine can use a lot less throttle, with the came gears, to get to cruise rpm....... and that is where the opportunity for saving fuel comes in; namely the bigger engine with the more hiway-friendly gears, loafing along, instead of buzzzzzing.
So that takes care of cruising

Now as to city mileage; Here again a big engine with say small gears in the back, may use the same amount of fuel or less as a smaller engine with same gears, cuz the smaller engine has to work harder or longer.
So it becomes a balancing act, and it all hinges on the low-rpm torque output, (which hinges on the pressure and volume) and the load (which hinges on the rear gears and applied throttle).

My take is this;
it is better to have cubes, lots of cylinder pressure, and low number rear gears,and drive with a light foot;
than to have less cubes, feeble pressure, a hi-stall, and higher number rear gears, because
that small engine will more often than not, be floored to get moving.
And where is the fuel economy in that........

In proof of that thinking, I offer my 367 at nearly 11/1 Scr (aluminum heads)and making ~180psi, that with a 223/230/110 cam went 106 in the quarter, yet with a 1.97 final drive (double overdrive) regularly made it into the 20s mpg in combined city/hiway, and one time in a point-to point over a full days driving,with a dedicated carb,posted 32mpgs.
There is no way I would put a 318 into that RamCharger for anything but straight hiway use, and it sure as heck would get the pressure pumped up. Jus saying; I wouldn't do it, is all. Shoot, it's hard enough getting a smogger-teen into the 20s at 3200 pounds, much less a RamCharger automatic, with nose-bleed tires on it.
For economy, get a Sprint or Geo, or a Rabbit or a Jetta, or a 323Mazda, or just about any 4-banger.

If you just gotta have economy the best answer is an overdrive.That'll tame your big engine.
Jus saying