"A" bodies had air also. It is when you try to do aftermarket air, then there is a problem. Especially the 66 and older. There is no direct fit evaporator to fit up behind the dash. It can be done but requires a fair bit of modifying. A under dash unit (knee knocker) is also an option.
When adding a compressor mount and drive to the engine, most aftermarket units, add a pulley to the front of the crank damper, forward of the PS pulley. This requires the compressor to be mounted pretty far forward, and the fan will hit the compressor clutch. There is very little room to move the fan forward to clear without getting the fan into the radiator.
I sell a compressor mount and drive that uses the OEM factory drive pulley (is located between the damper and the timing cover) and the "Sanden" style compressor. This allows the compressor to be mounted more to the rear, and also further outboard. There is no problem with fan/radiator clearence. also fits with most aftermarket intake and exhaust.