58 and 61 gm

[luvrbus]

Even if the evaporator is still there it takes a lot of work and $$$ to make it work by the time you bought a new condenser,expansion valves,fans and etc plus find a location now for the condenser.That was tied into the main cabin HVAC and the Carrier compressor was large enough to move the Freon You would be better off to find a used RedDot unit from a truck or farming equipment

[daddyoften]

One other thought on the a\c would be to check out RED DOT.  They do aftermarket a/c's and some construction equipment I work on has a hydraulically driven a/c compressor.  So you could run a small pump off the PTO and then a motor to a compressor up front and not loose the cool with long hoses.  I also wonder if the power-steering would have enough to supply a motor for a compressor 
Just thoughts.....
Eric