Here's a couple options:
http://www.vintagethunderbirdclub.org/
http://thunderbirdtalk.com/tbtalk/index.php
Here's a couple of good Y block (272,292,312) engine sites:
http://www.y-blocksforever.com/
http://www.y-blocksforever.com/
And this is probably on mr70's bookmarks, its a website dedicated to both attempts to recapture that retro spirit, the new-millenium baby birds AND the late, lamented, and largely forgotten Chrysler TC.
http://www.portholeauthority.com/