It depends greatly on the mechanical and cosmetic condition. There's one on eBay right now that looks immaculate, current bid is over $7000. And another in florida asking $9900 with low miles. On the flip side I've heard of a couple straight, non-crunched "parts cars" with bad engines or trannies going for $1500+. The usual examples will fall in between, say $3500-$5500 most of the time. Lots of things to watch for, particularly the inevitable cracked head. One with the head already replaced with the new, improved version is much more desirable, IMO.
Here's a partial checklist of things to look for:
http://buying.articles.mbz.org/checklists/124/
HTH,