71 Nova heater

I have recently purchased a 71 Nova over E Bay. Much to my suprise it did not have a heating system. What a suprise. I have been trying to find a heating system and found one and purchased it. When starting the installation I removed the sheet metal that was covering the original holes in the firewall. Well the heater core holes are on the far left side near the blower motor. After researching the set up I determined that the Nova was originally a big block or it had a/c. Since big blocks weren't installed on 71 it became obvious that the car originally had a/c. Now my dilema. Where can I find the inside heater box for a 71 Nova that had a/c. I am not installing a/c, but need that inide heater box to fit under the dash. I have no problem with getting the rest of the unit. Anyone who could lead me in the right direction would be appreciated.

Try www.classicindustries.com. When the page opens it gives you an error, but just click on the Nova/ChevyII box on the left of the page.