Oh no! another problem for post-1990 Spider owners... IAP list the radiator, but the webpage says "call for availability" so they may not carry it. How about Alfa Parts? CLICK HERE. The page does not say whether they have it in stock but it's worth a try.
Mr. Tiger, thanks for your reply, called this supplier as well today, same story, alfa quit making last year and none available. Hoped to find supplier with one "hanging around" but looks a bit dismal. Special order is best I can find for now.
I was a sales rep for SPI Distribution for some time. They are the largest manufacturer of radiators in north america and when we could not get a part we would call 1 800 radiator. I'll bet they have it and it will be a good price.
I just looked it up on 1 800 radiator and they have OE at $299 and after market for about half of that in stock about five miles from me in San Diego. You can go online and look it up for your area.