Aftermarket A/C for '66, /6 Dart

Keep searching. There is another thread about AC compressor bracket options for a slant six. It is very detailed w/ many photos (I contributed some). Of course, you can always use the factory RV2 and brackets. Dependable, but a massive beast. I think any year should fit (thru early 1980's), but be careful w/ truck engines since some had the alternator on L side. A Sanden is better and there were factory brackets for ~1978 Aspen/Volare slants, which you can see in the thread you will find. A knee-knocker is the cheapest option for the cabin unit and you can buy new (~$100 ebay).