Installing Air Conditioning in a 71

[48richard]

I have just bought a 71 C10 and am going to add air conditioning ( I live in Phoenix). Has anyone put in an aftermarket kit, or got together original parts and put in a non-a/c truck?
The kit seems simpler but won't look correct; also from looking at pictures of a/c and non a/c cabs the large holes in the firewall look different, so maybe putting in original parts won't work anyway.
Any thoughts on the best way to go?