Some of you out there advised me to = replace the pitted head studs on my '84 - how the H#!L do you get them = out?

I haven't found a single one that = will budge. I have two pairs of vise grips on them and I have a quarter turn of = flexure in the stud (I'm afraid I'll break them off!); I've applied heat, penetrating = oil, and banging with a hammer to no avail. What's the secret?