Rare Flathead Heads??????????

Hi, just wondering if anyone can shed some light on these heads i recently picked up. Just wondering how rare they are and any other info that you guys may have.
Cheers

Here's a start; http://thehotrodsofdearborn.com/sullivan-roadster.html

Looks like the Sullivan was Don, might have worked for Ford. Looks like you could have some fun searching the web for info. Or, go to the site's homepage, click the contact link and see if they can give you more info.