I put in aftermarket and factory ac units a few years after getting out of school . not hard but you need to be flexiable ,witch I am not any more. the prices in the 80's went from 350 inst to 1200inst, depending on what car you had,the cheveetts were the 1200 ones due to gm making a "safty car" that they never told any body about, & it was defrent, there was no way to tell untill you had it appart.so the boss tacked about $400.00 -600.00 more on to all cheveetts. kinda funny now that I think about it he was just sitting on his butt drinking& I was the one making the shop all the $$$ & I never saw any of that extrs cash. try jc whitney,fleebay,airtemp,frost temp there are a lot of ac mfr's out there. & 90% of the units are so well desigined that you cant tell them appart from OE. + they all have a better comperssor than OE. or just google it !! if you do it your self make sure you empty all of the compressor oil & replace with BG compressor oil.