After trying many different methods and gaskets here is what I think works best.
What you will need:
Fel-Pro VS13049C gasket set.
The Right Stuff sealer (or your favorite)
Vaseline (or some type of grease)
Prep the valve cover seal surfaces to be straight, true, and free from anything, including greases and oils.
Be sure the transition gap between the intake/head is as flat as possible and the intake gasket is trimmed flat too. A slight protrusion of the gasket is okay, but if you can get it flat it is best.
I modified a pair of side cutters to cut off this little tab of the intake gasket flush with the valve cover seating surface.
If you can not get it flush you can tap it down nicely with a prepped hammer.
"prepped" means the head of the hammer has been smoothed and polished so it can mash the gasket flat without imparting any marks from the hammer head into anything else.
This is how bodywork hammer heads are prepped.
Test fit the gaskets....they are not always correct out of the box.
Install your favorite gasket sealer on the valve cover over the entire "U" (the area including everything but the top rail along the intake manifold)
This area gets glued because the gasket sticks out into the void of the valvetrain area and becomes a shelf where oil sits.
Because the oil sits on this shelf it WILL eventually find a way out....The sealer helps to keep the oil inside.
I like to use "The Right Stuff" sealer for this part of the job, but apply just enough to coat, not ooze out everywhere.
Other than sealing the "U" part of the gasket to the valve cover I use no other sealer.
On the gasket surface that will meet the head/intake rail I smear Vaseline. I put it on like I am rubbing it into the gasket. Remove any extra that has rolled over the edge.
The Vaseline keeps the gasket from sticking to the head/intake rail for any future valve cover removal. I have reused this steup multiple times with no leaks or troubles.
The cork gaskets will eventually break down and begin to fail, but that takes years.
Before the gasket sealer dries I install the valve cover and torque just enough to set the gasket on the valvecover, but not fully torqued yet.
Let that dry per the sealers directions.
Once dry torque the valve cover bolts enough to squeeze the gasket and you are done....for now.
After a couple heat cycles retorque the bolts and things should be leak free until you mess with them again.
I like to check the torque from time to time, when I am under the hood for some reason, just to make sure they have not become loose due to gasket crush.
