The attached link is a diagram of your CIS system. The AAV is part Number 36 on the diagram. The long slender portion pointing left on the diagram will not be visable to you when you look in the engine bay. You will however be able to see the rest. My wife has the digital at the moment or I would snap a picture for you.
Jeff C
81 SC
http://www.pelicanparts.com/911/911_Parts/1978-83/1-7-2.JPG