Regarding the A/C and power steering: You have a Chevy SBC, I'm guessing that the PS pump and A/C compressor from any compatible engine to yours would mount up and fit in the engine bay. A PS pump is a hydraulic pump so as long as it sends power to the steering gearbox, it'll likely work just fine. Same with the A/C. An A/C compressor is just that, a pump. I'd suggest finding an R134a compressor that bolts up to your engine, any generic aftermarket condensor and dryer that fit, an R134a expansion valve or orifice tube, and flush the existing evaporator and then hook it up, draw a vacuum, and fill.