Hello, Friends. I purchased a 1972 Monte that came from factory with A/C, and it was removed by the previous engine rebuilder (for unknown reasons). I would like to reinstall this into the car, as it is a bit hard to drive in the bible belt in the summer with no A/C. However, the options are a 5 inch and 6 inch diameter pulley for the compressor. I am unsure whether it matters particularly which size I get, but would like to stay as original as possible. The build sheet is mostly illegible, except for the VIN and build location. Does anyone know how to find this information or does it not matter which one I get?

Tl;dr - What size A/C pulley should I get for 1972 Monte, none on car currently, 5 or 6 inch Diameter?