Air conditioning installation

What parts should I buy to make my cougar air conditioner work?

I would get with a local shop that is knowledgeable on classic auto air conditioning system upgrades. Assuming, that you have the under dash system in place. A Sandan compressor with 134A makes the most sense. A good shop has the ability to make hoses with combination of metric and 1968 American connections.
You should be able to use the compressor shelf bracket that you already have.