I just posted this up on the ofishal forum, it seems to fit here, also.
Observations in almost ten years of maintaining my C-10:
My stock valve cover gasket lasted 160k miles. Do not replace yours just cuz ya have a new one, they are re-useable.
Do replace the spark plug well gaskets(center row gaskets(??))
I've never had to replace the hold down bolt gaskets(rubbers).
Do replace the spark plugs
Do use a torque wrench on the bolts holding down the cover. Do NOT over torque!! Bad Juju if you do. (Think new/used cylinder head if you over torque and distort the cam bearing journals that the cover bolts screw into.)
Do NOT use a torque wrench on the adjuster nuts.
Do not remove the igniter cover, you can do it all with out pulling it off.
Record the measurements as you found them, for future comparison.(good practice)
Bandaids.
It's also a really good idea to have a couple of adjuster screws and nuts available, just in case.(especially if you go ahead and use a torque wrench on the adjuster nuts) The nuts you can get at a hardware store, the screws are a Ma Kaw item. I keep a couple of each, so far have never needed, but I don't use a torque wrench on 'em either. As Gary Murphy(Murphs') says, "It's better to have and not need than to need and not have."
Have fun! It's really not THAT bad.
And Vic S. added a good point, take a look at the hose clamp for the coolant hose leaving the thermostat housing to make sure the screw part is not down.
Also, be careful not to jar the t-stat housing, you could inspire a leak.