'58 Lark Compression, Relief Valves, and calcium buildup?

[DavesInvader]

Thanks everyone for the help on the compression test. I tried cranking it with the battery, couldn't get much higher than 55 psi. So with the compression relief valves unhooked I tried turning it at the flywheel with a ratchet. Nothing better but I noticed I could still hear significant air leaking out around the relief valves. So against better judgment, I took the compression relief chamber assembly off the head, then ultimately took the head off (figured I didn't have anything to lose at this point!) It appears the pressure relief valves were seriously gummed up and were not able to close all of the way. Also I think their o-rings are shot, the valves wiggled surprisingly easy from side to side (or is that normal?) Another curious thing... when I pulled the compression chamber off the top of the head, I discovered that a large part of the bottom half of the bottom side was literally packed with white deposits (calcium/lime?). I'm guessing it is evidence of a gasket failure, but if anyone has any ideas I'm open. Here are a few pics.

http://mysite.verizon.net/res78w95/boat/id2.html

Not very good pics but you get the idea. So a few questions... do you folks advise that I find new o-ring seals for the compression relief valves or just clean them and their seats up? And what the heck is the white stuff from?

Also, while I'm poking around in there, anything else I should look for? The last time I had the head off anything it was an '85 Chevy Cavalier and things were much different!

Thanks!
Dave