Which port to charge 1983 El Camino air conditioner?

A 1983 El Camino doesn't have a port to charge the air conditioner in the way modern vehicles do with easily accessible service ports. The R12 refrigerant system (used in that year) requires accessing the low-side and/or high-side service ports which are usually located on the compressor or dryer/accumulator. These are not typically exposed and require removing some components to access them properly.

You should NOT attempt to charge the AC system yourself unless you have the proper training, tools, and safety equipment. Refrigerant R12 is also being phased out and working with it requires specialized knowledge and handling procedures.

To charge the AC system of your 1983 El Camino, you should take it to a qualified automotive air conditioning technician. They have the necessary equipment, knowledge of the system, and will ensure the job is done safely and correctly. Improper charging can damage the system, expose you to dangerous refrigerants, and lead to significant repair costs.