OK. That’s an EFI engine, known as an ISC if 8.3L. They start and run great, and are self contained. I am preparing to do the same. Was the excavator 24 volt? Likely. ECM on it is selectable between 12v and 24v. Electric lift pump on it would need to be switched to 24v if it is 12v, or run the entire engine on 12v. Same with intake grid heater if it has one. Easy to do either way.
Fan drive is missing, those are not cheap. That engine will need a front mounted charge air cooler. If you are putting it in front of a stock M939 auto trans, those are somewhat unique engine flywheel housings, you’d need one of those if the truck does not have it.
Otherwise, just need an electronic throttle pedal, one from a Cummins Dodge Ram works. Just power and ground and she’ll run.
That is a 4 valve engine, so you can put factory Jake brakes on it. I did on mine, but engine not in truck yet.
That turbo will have to be spun 180 degrees so exhaust faces rear, then just re-clock the compressor housing.
The M939xx engine mounts offset the motor heavily to the pass side, just FYI. Oil pan has large recess for front prop shaft. But the base mil 8.3L one fits the newer engine.
My M925a2 8.3L engine is for sale if you want exactly the engine that came out of that truck. The EFI engines are cheaper to buy, I think people are scared of of a few wires. It is really just power, ground, and the accel pedal wires.