Conversion x15 2250 - 2350

[JimT]

So, since this is a bit of Q&A here, I've been wondering, why can't someone drop in a newer engine with it's corresponding ECM? I assume at least part of the problem has to do with the other OEM and 3rd party systems, but is there any reason why those other systems and the accompanying wiring can't be swapped out instead for newer components (assuming they are available)?