The best version of the 1kzt e to get is the later 90 series as there's less chance of head failure. Newer and improved version. But at the end of the day... they are absolutely brilliant motors!
There's quite a few parts that you need to source when going from a 90 series. You need:-
Sump and oil pickup. Ideally from 3.0 surf td, mk5 hilux d4d, 120 series d4d, kzj70 series or not ideal but works toyota granvia 3.0td.
Power steering pipework from 3.0 surf or mk5 hilux or kzj70 or fabricate your own.
Bell housing setup with clutch fork and starter motor.
On the 90 series the engine mounts that bolt onto the engine are 140mm long and for the 70 they're 110mm long so you can use the ones off 120 series, granvia, surf and d4d hilux 5 or kzj 70 etc (narrower chassis)
You can modify your lj engine loom to work with the 1kz.
The exhaust/turbo outlet is a bit of a stumbling block... if you set the engine high you can get away with using the Granvia but very tight. Turbo outlet from a 4 runner can work with a body lift. The 90 series turbo outlet is completely out as it will not work.. So a bit off a bespoke outlet is probably the one to make up.
You will need to block off the egr and remove the butterfly from inside the inlet manifold.
If you can get hold of the airbox off a 3.0 surf then it actually fits!!! Even though it's designated for the other side of the engine compartment... then use the same pipe off a ford transit 2.2 to connect the airbox to the turbo.. fits perfect!
You need a different radiator,,, my favorite one is the aftermarket fully alloy one for a hzj75, it's the right size but you have to make up a way to mount it! Bought a surf alloy radiator and it's too tall and wount let the bonnet close!!
You will have to ditch the electronic pump and you are very lucky in the fact that you can fit the 2lt manual fuel pump to the engine.. you will need to set the timing up perfectly and to use a dial gauge set to 1.57 (best setting I've found!) You can then tune it freely!
When you fit the engine you'll see that you will need to either move the chassis engine mounts or be inventive!
I'm sure there's a couple of other things but it's best to be aware that there's a bit to these engine swaps from a 90 series!
Good luck with it.... don't let it scare you... with the knowledge and careful planning it's a great way to get your lj going really nice!
P.S. Keep the thread going as you take the plunge!