The compresser that TallHair is referring to bolts to the engine. They are VERY heavy, and hence are expensive to ship. There are new compressers by a company called SANDEN, (not Sanderson) that are smaller and easier to deal with.
As well there is a company called VINTAGE AIR that sells complete kits with the Sanden compresser, all the brackets required to bolt it to the engine, the condensor that goes near the radiator, the Mark IV interior unit pictured above that bolts under the dash, plus all ducting, wiring, controls, etc. ALL NEW. This is a much simpler and less invasive installation, and leaves your existing dashboard untouched. Installing factory AC in addition to the engine compartment stuff, needs a different dashboard and heater/AC unit behind it, and is a very complex task.
Unless you know what you're doing or you have someone who you trust to do the work for you who is intimately familiar with the year make and model of your car, retrofitting original factory AC into the car is
really difficult and more work that I expect you want to deal with or pay for. I suggest you explore the Vintage Air kits. They are much easier to deal with by a mechanic, and doesn't require the intimate model specific knowlege, and doesn't require things like removing dashboards and front windscreens etc (something required to put factory in-dash AC into your car).
Here's a Google Search just for Vintage Air. You can see a lot of vendors sell Vintage Air products, and they get decent reviews.
vintageair - Google Search
Here's a link directly to Vintage Air - they have a huge catalogue of parts to put in-dash AC in to cars that don't have it, or to improve cars with existing indash systems that need repair or improvement:
Vintage Air - Inventors of Performance Air Conditioning - www.vintageair.com
As well, and this is what others and myself were referring to, Vintage Air makes UNDER DASH SYSTEMS which I think you'd be much more satisfied with. Here's a link to Vintage Air's page on their
Mark IV and other underdash systems. Vintage Aiir makes the new and improved version of the old Mark IV unit, and can taylor a complete system for your car with all new parts from front to back. One stop shopping with detailed installation instructions and telephone assistance too.
http://www.vintageair.com/2016 Catalog/2016 Vintage Air Catalog 50.pdf
Good luck.