I have not done a conversion, but I have reassemble both A/C and non-A/C cars. I do know the cowl fresh air vent hole on the drivers side is blocked off (no hole). The factory A/C air box uses only the passenger side cowl hole. You might be able to just leave the drivers side in place anyway. The heater controls on the dash will change. There is a water vapor drain tube from the air box that exits thru a hole in the passenger floor pan. There are 6-8 vacuum lines from the heater controls to the air box and two of them exit thru the center of the firewall and connect to the vacuum canister and heater control valve on the passenger side. The glove box will need to be swapped with the shallower A/C version. A large cutout in the firewall for the evaporator coil tubes to exit thru is needed, you can see a "comma" shaped imprint in the firewall for it just below the heater coil tubes. If you have a power steering cooler on your non-A/C P/S pump now that will need to change to one that wraps over the top of the A/C compressor. The wiring harness running along the driver side valve cover may need to change if it does not already have the wire for the compressor (a square plug located at the front end of the harness near the plug for the fast idle solenoid). The crank pulley needs to change. A/C cars came with a larger radiator and fan shroud than most non-A/C cars. Then there is the A/C belts, tension-er pulley, hoses, compressor, etc. which I assume is in the complete factory setup you are getting
I am sure I have missed something...
I can post some pictures if needed.