Mine also broke this summer on our 1981 H30. It is a Y shape bronze casting with the cutless on the bottom of the Y. I called Hunter and they said they were made by Dahmer Marine and gave me a phone number. I looked at it closer and found Dahmer Marine on the casting under the layers of paint. But no one answered even though they have a website and showed the strut I wanted.
http://www.dahmermarine.com/Struts.htm part No 2010.
I eventually found out that Dahmer was apparently sold and the parts are now owned by Millers Island Propeller, as of quite recently.
http://millersislandprop.com/site/news_detail/dahmer_marine_hardware/
I just ordered a replacement from Millers for $425 (ouch) and am awaiting delivery.
I considered having one made up out of stainless steel and am still not sure whether that would have been more expensive or not. This seemed more likely to fit exactly.
struell