For a DD I usually wouldn't worry myself, until this past winter. While the snow flew, I was slapping together a motor for a friend who swore up and down on his stock head bolts. That was, until I did the unthinkable to him, and grabbed the torque wrench and broke one off. I dont recall the specs off the top of my head, but I was only half way to being tight.

Now, he's got ARP's in his motor

The head doesn't ALWAYS get warped either. Its typical and a GOOD probability, but not always the case. In the same sentence, NEVER put a HG in an over heated motor with out having it checked though. If its still no good after being decked, then your block is probably warped.