Engine Mechanical problem
1996 Cadillac El Dorado V8 Two Wheel Drive Automatic 120000 miles

i have the cylinder covers pulled for a head gasket replacement and valve job and i'm stuck on getting the cylinder heads off.
also.. i'd like to know what these things are and how and if they need to be removed.




looking at them i'd be surprised if they actually bind in anywhere and i've almost stripped them with the 10 mm hex. is there a special allen wrench for them (i think a 10.2 would be perfect or another way they come off? or are there any other bind points that i may have missed? having a very hard time getting these off.

honestly this is my first head gasket job and if anyone had a link to an entire online chilton's or haynes type manual for this car it would be verrrrrrry helpful and i'd save you frequent posters a bunch of time...not a single auto store i've called around here has had one to purchase

thanks in advance.. the help is VERY much appreciated.

max