Retro fitting an AC setup.

You didn't tell us what engine it has. Most (all?) w/ the floor shifter had a 273, which is easier since same as later small blocks. Your engine bay is 1" narrower, but shouldn't matter. If a slant, there is a long post on options. The factory AC climate box isn't a good choice since those cars had a different firewall. An after-market behind-dash unit seems better.