You'd have to see if the bell housing will mate to your engine and transmission to know if it'll work. So, either bring it with you, find out the information on the web, or you might be able to get away with making a cardboard template to see. Now, I'm no master mechanic and I've never had to deal with clutch and flywheel things, but I'd imagine as long as the flywheel and clutch have the same bolt pattern and size between the two engines, it should work, right? If anything, you can just buy a new flywheel and clutch just to have new parts for many Km's of use, and (hopefully) there'll be no worry about if it'll fit or not.
I'd think you can try the Z24 stuff and if it doesn't work, what's another trip to the bone yard?
Again, I'm no master mechanic, just giving some though into this.
Really though, with enough planing, money, time, and fabricating, you can fit anything into that truck. People do put LS3's into Miatas, after all!
Did Nissan ever sell the Diesel Pickups down under? All I can remember is that if was a European thing. Maybe you can find one of those engines. My year truck (91) Came in Diesel over the pond, I know that. And it does have the same transmission code you posted. Maybe the Diesel shared a common transmission? Then you can have Diesel without changing the transmission, or possibly anything at all. Just make sure you get as much harness and engine control stuff you can get if you don't feel like doing it all by your self. Sure, it's possible, but do you
really want to do all that work?
There's my thoughts. Good luck on this, I wanted a diesel truck, too.