I would think the basic air conditioning mechanical fundamentals under the bonnet would hook up to a 260Z, but that would be the end of it IMO.
The 280zx centre dashboard layout and demisting plus side vents and fan control are vastly different from the 260Z, you could surely pick up another unit out of a wrecked 260Z 2+2 that you could configure to work even using an auto electrician the under bonnet air cond compressors often seize, the systems haven't been retroed for the new refrigerant gas which is simple and often the thermostat for cooling are damaged
As I recall back in 1974 most 2+2's from 1974 - 1978 had 2 models, a poverty pack or a luxury pack, the difference being am/fm radio cassette and air-cond...that's it! You are unlucky not to have air mine works a treat but getting the ducts into the right spots is back breaking. Lynton
