It will insall but it won't function properly. I learned the hard way. The cars w/o ac had what I belive was called Astro Ventelation. AC cars didn't.

The difference is that there is a cut out in the chassis for the Astro Vent. Some of these folks with a bunch of salavge firbirds might be able to send/post a picture showing the w/w/o cutout for astro vent.