Pipeline,
I guess you already know that there are a lot of differences between an a/c car and a non a/c car. Dash, heater box, heater controls and the firewall. Actually the cowl area is different as well. I just sold a parts car that had an a/c dash in it. I'll check and see if the guy is interested in selling it. Personally, I think that you're lucky to have the non a/c setup. My 71 is an air car and I removed the a/c stuff. I wish the firewall was a non a/c firewall. I will probably convert it later on to make the car look right. I added a shaker hood last summer and shaker hood cars weren't available with a/c. I have a lot of the stuff to convert your cuda to a/c. I'll get with you later. The stuff's not going anywhere, so no hurry. My advice is to forget the a/c. We drove all of the way to Branson in August and never missed the a/c.
Here's a pic of my wife's 73.