I have been told that wheels from a 81-83 z will fit on my 1972 Z. Before ordering I wanted to know if this is true and if there is any aftermarket wheels available?

Yes, and yes.

Check out Mototsport Auto, for current wheels and look at ebay, there are several sellers who have current wheels for our cars.

WIll

I you end up using Nissan factory 81-83 ZX Wheels, You must use the special Nissan lug nuts. Very few aftermarket sources are availible for this special lug nut. Other aftermarket wheels use more common lug nuts

Depending on how much you are paying for those wheels, there may be some much better options out there. I got my Konig Rewinds from Motorsport for about $550. I couldn't be happier. As mentioned, try Motorsport and eBay. If it does not specifically say its for a Z, you need 4X4.5 bolt pattern and a RWD offset. Otherwise you could get the adapters that will allow you to use FWD wheels, like for a Honda. That makes your possibilities almost limitless. The adapters can usually be found on eBay, but I think Motorsport may sell them too. You could probably find them elsewhere on the web as well.