I am looking at installing a factory A/C system from a '79 into my '78. Is there going to be a problem with the newer R134 refrigerant in this old system? What will need to be replaced? Am I better off trying to install an Antique Air system instead?

 

You are probably better off upgrading to the newer stuff. You will need to flush the entire system of all the old oil and refrigerant and change out the drier/accumulator for sure. Any hoses that have the inline can or muffler looking thing will need to be replaced also. Don't forget the orfice tube for 134, it should be red I believe. As long as you do a good flush and pull a vacuum, you shouldn't have any problem with 134 in the old system.