Aftermarket A/C systems

The aftermarket kits run ~$1000 for the full setup, or ~$600 for the compressor w/ brackets. You can do much cheaper by finding a factory system. The RV2 compressor was most common thru the 1980's, but quite heavy and bulky. A Sanden would be ideal. Some 78-79 Volare/Aspen w/ slant six had them from the factory. Rockauto shows the Sanden for "dealer-installed" 318 engines around those years, so you might luck into brackets at a junkyard. There was also the small Chrysler C181 compressor then, but had early problems. The best compressor/brackets might be from the latest 318 before it became the 5.2L Magnum (~1992?) w/ serpentine belt. Google Images helps. On ebay, view new universal condensers ($50) and under-dash units ($100).