Today I was in the middle of removing the cylinder head bolts. I was able to loosen all but one. The head is stripped so that my socket won't grip. Anybody else have that happen? How can I remove this last bolt?

Another question I've got is the "pin" that holds the timing chain guide. I screwed a 6mm bolt into it with a socket, washer, and nut, but I can't get it to budge. What I'm doing wrong? I'm afraid that I'll break the plastic chain guide.