Magnum swap starts, does not run

I would check the fuel injectors for a good spray pattern.
Very common for fuel injectors to not work after setting for long periods. The pintles stick.
Just ran into a similar issue with a hemi that had set for about 2 years and only had 3500 miles on it, it would not start .
I pulled the fuel rail off , injectors attached to it and cranked the engine with the fuel line and injector harness connected , not a single injector was working with proper fuel pressure and noid lights firing ,previously tested.
I used a fuel injector tester which pulses the injector like an ECM , then tapped the pintle end with a screwdriver until they would pulse . Did that with all 8 , re-installed the fuel rail/injectors and it fired right up.
You can take a 9 volt battery and jump the injector and do the same thing, just not with 12 volts , as you can fry the injector.
The computer pulses the injectors , but you should be able to feel and hear a clicking of the fuel injector as it works with the 9 volt battery. Its basically an on/off solenoid.
Just need to make sure your all your injectors are working properly first.