First off let me admit, I'm biased towards Mercedes turbo diesel motors, so if I come off like I'm "trolling"... Sorry in advance!
Secondly, I know nothing about the newer Cummins motors ( I know quite a bit about 4BT, 6BTAA, & 6CTAA motors though).
My first concern would be the "electronic" integration of the motor to the vehicles "brain".
My second concern would be the your wife's work vehicle going FORD ( found off road DEAD), and putting her and the dogs in peril!
Third being that now in "modern times", you/ she will get "laughed" out of most repair shops because the new breed of mechanics only know "plug & play" ( goes back to my first concern).
ALL NEW DIESELS now have VERY complicated injection & emission systems to meet federal standards ( you can thank "bonehead" California for that!!!). Thus, making swapping from gas to diesel a more or less "mute" point!
Here is a picture of the Mercedes OM602 DE2.9LA that I put in my Jeep Scrambler.
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