The first question is do you want your car to look like it has stock AC or do you want a working system? You can find original frigidair systems...dealers in the states installed them so there was some variablility. (I got one from my 66 1800 with the Phoenix dealership's install sticker on it!) They are huge and the compressor looks like a lawn mower engine and takes way too much power, but it does have lots of chrome and look cool...however mine only has three vents all in the center unit, so it does not cool well. The aftermarket hotrodder units are much more compact and use rotory compressors so they cool better and take less power. I have seen folks mix and match...original under dash unit for looks with modern rotary compressors, etc with success.

So...price check and decide on what you really need.

p.s. We put a heat reflective shield/insulation on between the roof and headliner and on the floor of the amazon wagon and 1800 which made a huge difference in Arizona (dark green cars), and helps now in Washington the month of warm weather too.