Hey Ken,
If you want correct belts for your '72 this is who I would go to.
http://www.quantaproducts.com/home.asp
Every part that I have ever gotten from them for my '69 has been spot on. They are not local, they are in Rising Sun, Maryland but give them a call and I would be willing to bet that you get what you need in a couple days from them. In addition, there belts are actual reproductions of the originals, if that is of interest to you.
Let me know how you make out.
Rich