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

IF your getting all the electrics and wiring, I would would use the new automatic transmission and transfer case. If it was a 4x4.
There are other things to grab as well:
- fuel tank/ pump.
- exhaust system.
- rad.
- steering column.
- fuse box.
Doing a swap like this you should really try and find a whole donor truck. You'll be missing so many odds and ends it will nickel dime you to death!