Trying to pull the head on a 93 to see if the valves are bent because I'm not getting compression. I've broken or rounded several sockets. Today I got a different impact set with thinner walls and was able to get 2 of the final 3 bolts out. Now I'm stuck at the one in the bottom corner near the cam gear.

(FYI I did intend to do these all in the right order, and started that way but had to modify my strategy a bit when I got stuck)

I've been sitting on that one for several minutes with an impact with nothing and the breaker bar + 6 point 14mm is starting damage the bolt head or it will pop off.

I've tried WD40, liquid wrench, brake fluid, acetone... Pretty much everything I could think of but nothing. I don't have a torch so no luck there. (I live in an apartment and all my tools are in 2 red tool boxes.)

But another question. After cleaning out the "oil bath" under the cam,I saw what looks to be a hex shape in the head. Is that actually something that unscrews or just a design in the head?