I have a 72 SS that is currently an air conditioned car from the factory, I would like to take the air unit out of the firewall and install a regular heater unit on the fire wall and in the cars interior. How much trouble is this and will the new heater box cover all the holes in the fire wall left from the air unit?
Thanks for the help

It should be possible to swap it out. Also look into taking that A/C box apart carefully as that is a part that is not reproduced currently and the Camaro guys will pay you top dollar for one in good shape.

Big Dave