My guess is the engine itself is the same but it won't be plug and play, different harness, wiring, etc. Don't think you'll find an exact answer to this. Why is it needing replacement?

 

Bottom end is knocking, from what I understand it was ran for 30k miles without an oil change

 

Maybe call one of the major engine rebuilders:

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From years of reading this forum, I'm going to say there are zero differences, but you'll have to have the software to program a handshake between the new engine sensors and the existing ECU.

 

My 2019 3.7L has a MAP sensor vs a Air Mass Sensor for the fuel injection. So intake manifold has a mount for the MAP sensor. but I would agree that the Long block is the same and that is what matter. if the ancillary stuff from the original engine is transferred over.

 

That is the only problem with a 2015, They have a two wire Map Sensor where the newer engines use a three wire, Also on the 2015 the map sensor is mounted in a slightly different location.
In theory you should just be able to move your current Map Sensor and the related plumbing over to a 2015. It is just air intake plumbing.

 

I thought the 2015-2018 3.7L NA had "air mass sensors" mounted by the air filter outlet before the throttle body.
The 2019 has a MAP "manifold absolute pressure" sensor mounted on the the intake manifold after the throttle body.

 

This is just old news trying to explain this since it has already been explained 100 times in a dozen different forum threads.
There is a TSB from ford that says the new waterproof air filter cover that came out in 2018 will not fit the 2015 because of the Map Sensor, Everybody with a early model transit wanted that cover and this has been endlessly discussed. (No more "turd" )
I guess it did not matter to you because you have a 2019.

In 2016 the map sensor was moved to its current location.