there are diffrences from a N\A to a T\D isuzu engine.
the valves are smaller in theT\D
the angel cut on the rings are a little diffrent
the compresson is the same.
as far as i know the crank is the same.
timing is 15 for N\A 10 for T\D.
the piston pin is a few MM bigger for T\D.
the pump has boost compensator, thingee LOL to limit fuel to the engine at times of low boost.
staying under 8 or 10psi is best for longer life.
now then theres the rods.......
theres only about 800 sets of gen 3 rods in the USA, and most are in troopers.
theres also GEN2s but i dont know how many sets of those are out there.
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i figure this will help you and others doing diesel swaps and or repare.
and yes the part numbers are the same on GEN 2 and 3 i have no idea why.
hope this helps.