5.9 magnum swap

Which way I go as far as engine will depend a lot upon the teardown and inspection of my current 340. I already have the carb version AirGap for that engine. Just thinking that between running a carb for years, and not knowing if there are hardened seats in the X heads that I stand a good chance of weighing between a full rebuild, or finding a 5.9 to put in its place since the 340 isn't original anyway. I was figuring that the ThrottleBody would be a step up from carb, while also getting a block designed for a roller cam, but knowing that I don't get the full benefits of individual port injection, also keeping the look of a 68, and not having to find a place to hide a control module. BUT say I decide fuel rails aint too ugly, where do I find the wiring info to wire up the module, & is there a complete list somewhere of what to salvage from a donor vehicle? Besides the fuel system, ie-sensors, wiring, etc. This will be connected to an 833 trans, is there concerns about internal balance 340 to external balance Magnum.
I didn't know there was an RPM AG FI for magnums.