Magnum MPG daily driver

That would depend on what your looking for out of your swap. The 318 may get better mileage than the 360 by that 1-2 mpg tune, but if your really looking for power, it's the 360 your looking at. For a mild upgrade in power and just a cruiser, the 318 will do great.

Between the computer, EFI, overdrive and a better and newer engine, either engine is a winner.