adding magnum 360 parts to la 360??

question #1..i currently have the stock 78 heads..i know the magnum intake wont fit the stock heads, if I change to the magnum style heads, I should be able to use the fuel injection from the newer motor??..what parts do I need to get from donor vehicle to make the fuel injection work? and does anyone have a link to where I can find the wiring diagram to make all this work..

There are a few things to consider and needs to include question 3 for some of the discussion.
1. Will the stock PCM be able to handle the aftermaket cam and / or can it be programed to do so? yes, just need to find the right person.
2. If installing an overdrive trans, will it be an RE or RH trans? This is where the PCM thing comes into play.
Find an FSM from the donor if you decide to go that route, not all iterations of the magnum harness are the same between years and vehicle line. I'd recommend harness, power distribution center and PCM from the same vehicle. The harness can be cut at the firewall as everything needed to run the engine is in the engine bay harness. Preferably unplugged not cut though.
For factory EFI you'll need the intake, throttle body, injectors, harness, PCM
For any EFI you'll need a correct high pressure fuel system, preferably a return style with an adjustable regulator.

question #2..i also want to switch from the single belts on the old style to the serpentine belt system like the newer motor..the duster has power steering and I will be adding a vintage a/c system to car..what parts do I need to convert my motor to the serpentine system? id like to use all factory parts since they are easily obtainable at local junkyards..

The serp setup is fairly straight forward, you could use brackets / pieces from any magnum, the mag heads will have all of the bosses drilled for the mag brackets .
Couple things to be aware of:
1. Chrysler used 2 different A/C compressors. Mounting holes are ever so slightly off for the compressor. You'll need the correct bracket for the compressor.
2. Power steering pumps have the same fitting as the federal pump. I used the line off my old /6 and tweaked it a little to line up.
BUT there are at least 2 different brackets for the pump...truck vs van. The van bracket puts the pump low enough to clear the stock battery location. If you use the truck bracket, you'll need to clearance the tray or move the battery.

I'm sure there's more, but this will get you started on what direction you want to go.
I really think that the main issue you'll have with the stock EFI is that it will have to be reprogrammed by someone to support the new cam. Cruise the dakota-durango forums to find info on that. Lots of guys doing amazing things with trucks.