thinkin of dumpin the duster AC?

I would leave the AC box regardless. A lot of work to change, for minimal benefit and would make your car less valuable. If you don't like the monster RV2 compressor, consider replacing it w/ a small, efficient Sanden. There are brackets for the slant (have one). Even simpler, if you don't have power steering it looks like one could mount a "York-to-Sanden" adapter on that pad, similar to what member Syed in Malaysia did.