OK, attempt 2.

Find a wreckers wrecking a complete HX or HZ V8 with factory air, or buy a whole car. If it is a whole car leave alone. If it is in a wreckers, buy the firewall cut. Unbolt/unscrew everything off the inner guard and leave it hanging, attached to the firewall stuff. Unbolt the compressor and take the whole assembly, brackets etc. Get the pulley off the engine. Also get the condensor and aux fan and wiring. Cut across the windscreen pillars and under the floor to firewall joint, and take the entire dash, harness etc in one piece. If you can do a deal to take back the column, instruments etc later do it. Undo the compressor hoses and take it in as big a piece as possible. Get the inner guard too. Use tape to seal up all hoses, compressor, condensor etc to keep muck out.

On your car strip the dash, instruments, glovebox and dashpad. Remove the ducting and the inner/outer heater box. Remove the left side fresh air intake. A/C doesn't use the right side air intake, so if you like you can leave it in place and have 1 x control slide and cable or remove it too.

Off the A/C firewall, remove the evaportator box and heater box inside the cabin. Look at the A/C firewall and look at your and you can see the A/C firewall has 3 x extra holes. There is one big one in the middle that the A/C wires and vacuum tube comes through, and 3 x overlapping holes that the heater tubes come through, often these 3 x holes are filed into a slot. On your firewall there will be dimples showing you where to holesaw these. From memory the bigger hole is 32mm, and the others are 16mm. So go and make them holes! Once done dress with a file and paint the bare steel.

Now it is just a matter of transferring it all over bit by bit. Mark where each vacuum hose goes before disconnecting, you can leave them all connected to the controller. Check the operation of the vacuum operators first, sometimes they are no good. If the foam seal on the heater door is had it, replace with a new bit of foam. Make sure you put the A/C insulation on the firewall, hopefully it will still be on the donor firewall. Put the vaccum controller in place, run hoses etc. When you go to put the LH side air intake in place you have to drill an extra attachment screw hole as the non A/C car will only have 2, just dress the hole before putting in the screw. If you use the A/C blanking plate on the RH side you'll have to drill its hole too. You may have to make up new foam seals around the ducting joints. You should have the cabin all back together in a few hours. You can test all the operation of the gates and fan. From memory you have to use the factory A/C car's wiring harness too, so it is important it is like yours ie if you have HZ use HX/HX. That or modify the fuse box to suit.

Now put the A/C inner guard on your car and attach all the A/C fuses etc.
Fit the compressor, condensor etc. It may pay to get the condensor and compressor serviced, possibly even buy a new condensor if it is stuffed.
Take it too an A/C mob and get them to get it all going. They will probably fit a new dryer/filter. As above you may need to get a reco compressor. If you are not that set on originality you will probably be better off adapting a Sanden SD508 compressor like Commodores had.
Then enjoy cool driving.