Compressor wires
There is a short black one that goes to ground.
Then there is another black that goes to the super heat switch on the back of the compressor.
What may be misssing is the thermal limiter fuse and connector. The thermo limiter has a fuse that will blow if the freon gets too low. It prevents burning up the compressor. The connector has three wires. The balck wire that goes to the back of the compressor
A dark green wire that goes to the ambient switch
dark green wire with white tracer goes to the clutch-this is the large pulley at the front of the compressor. When the fuse blows the clutch can not lock up and the compressor will not "work"
You have to find some one that worked on these-from like 1971-1976. They will know what to look for right away. That would be a guy over 60 years old.

The above may be slightly incorrect but the main thing is to find a person that know what he is doing.
There is to much in the shop manual to print out.