Factory eco injection.

OE Magnum wouldn't be that hard. Here's an adaptor for the crank sensor:

3.9/5.2/5.9 ENGINE - Crank Sensor Adapter - HiPoTek

There are reasonably simple solutions to any of the other issues that would come up.

For most of us, OE Magnum would be the cheapest option to get MPFI on a small block, and when you're done all your replacement parts are catalogue Chrysler pieces. Just go down to a local yard or find a guy parting out a 2nd gen Ram and pull the harness, PCM, distributor, intake with injectors, sensors, and throttle body. (While you're at it, just could pull the 5.2 or 5.9 and use the engine too, but that wasn't the OP's question.) I got that entire list or parts off a guy for $100 CAD. He was parting a truck and only wanted the engine.