The last engine I pulled out of a car, The head was so seized I was able to get get it out with a chain and spark plug eyes. There were no head nuts on any studs! And that's after liberally dousing them with WD 40. They had every reason to let go, but didn't. I put the nuts back on and hit them from the sides and blew out the holes around the studs and soaked them in WD 40 over night. and hit the head with a lead hammer. Eventually, it started to move to where I could get a knife blade in between the head and the block. It fought me all the way!
Terry