Compressors

I have factory A/C in my 1966 Dodge Dart ,can i install the newer style Compressor and keep the original parts
Yes. You will need brackets for your engine. See Bouchillon Performance Engineering, Classic Air, and others. If a slant-six engine, search for the thread on compressor options. You might prefer to install a new parallel-flow aluminum condenser, but not required. You won't need the metal resonator on the large suction line, which you will likely replace. Most Sanden have #8 hose outlet and #10 suction, and O-ring fittings are most common. I think you can cut the ferrules off your factory hoses to re-use the metal fittings on new hose, if the same size. If not, there are adapters. Most liquid lines are #6 hose. Install a new filter/drier. No reason you can't use the Mopar expansion valve and condenser. I wouldn't use R-134A since being outlawed, plus its oils can absorb moisture to form corrosive acids. I used Duracool refrigerant with their Oil Chill oil (I think Hella PAO-68, compatible with all refrigerants) in all my cars, even my 2002 after the compressor failed. Duracool and Envirosafe are compatible with your OE mineral oil. Don't believe the web silly rants about HC refrigerants being "explosive". Those are from fools who know nothing about combustion. Carrying a newspaper in the cabin is a bigger fire risk. Replace all hoses w/ new barrier-style hose (Viton liner). If you don't have a ferrule crimper and won't have a shop make them, use Oeticker stepless ear clamps (ebay, 2 at each fitting is prudent). Some say the the similar PEX clamps work (Home Depot, never tried).