In the question, there is no specification about the type of engine...
Differences i noticed between turbo and non turbo diesel, (ships) engines
Not all where found on the same engine and I am sure I have forgotten some of them already
Turbo, compression, camshaft, pistons, inlet and outlet collector, bigger diameter exhaust, different material of the bearings crankshaft, bigger oil pump, air cooler, oil cooler, piston cooling (oil).
Lowering the compression ratio, on the same motor block, (turbo) was done by the different pistons.
The turbo pistons had a different top that made it possible for an extra overlap...in and outlet valve, together open for a longer period.
This overlap was made to cool the top of the pistons.
I hope, I still have it all a bit wright, ships engines are now 25 years in the past and the brains are already a bit fading.
For Transit, there are plenty of good Transit brains on this forum