Certain Early Hilux ac parts are either hard to find or expensive. The ac was a dealer add-on (as I understand) and not integrated with the heater/fan as later gen truck units were. The evaporator core is not being made (I couldn’t find a new one anyway). The empty core box is something like $400 from Toyota but I’m not even sure it’s actually available.

Im in the process of adding ac to my 83, after searching for almost a year I finally found a donor truck from same era and pulled everything. Luckily most of those parts are still usable. I checked on using a system from a later gen truck, and although anything is possible, realized it would be very labor intensive with a lot of modification and probably not look very good.

well In reality it’s a 3rz swap and adding ac at the same time. I’m about half way through but most of the ac is just bolt-in from here. I’m central Phx off the 51.