2014 hemi 5.7 replacing a 318 in a 1977 power wagon 4X4 ?

A motor that new may not play nice with a different transmission. The main question would be what was that motor in front of to begin with and what all did the computer run stock? If it's an integrated ECM/TCM combo you may be out of luck on that front. The new engines have lots of bells and whistles that haven't quite been sorted out by the aftermarket crew yet. Stuff like VVT and variable length runners haven't quite found a place in retro swaps to date, though with enough time and effort I'm sure they can be done.