There's a set of W-30 F heads on Ebay. I thought one way to identify them was that the center exhaust port divider came out flush to the head surface. In the picture, in the listing, it looks like the divider is recessed. Is this something that changed in production, the way some some of the W-30 intakes are cast Oldsmobile 455, and others are cast Olds 455?
http://cgi.ebay.com/ebaymotors/1970-...QQcmdZViewItem