The other half of that A/C box (the main box),plus adding the condenser ( the radiator looking piece) plus locating the pump and receiver drier. A bigger more capable radiator Also what type of refrigerant is available to you there. (r-12. R-134, R-1234YF, or YZ1234) will affect your system efficiency, et alone what is available over there. This will give you a better idea as to what I'm saying as far as pieces/parts and placement.
https://www.youtube.com/watch?v=jRqLr_jRY80
Some good photos here:
https://www.motortrend.com/how-to/qu...system-install
I would check out pictures of Classic roadsters Cobras with the bigger dash and a/c vents, look at how their components are installed.