By the sound of the description on the 3M Super Weatherstrip Adhesive, makes it sound like it would work well to seal a valve cover.
Adhesive is a strong, flexible, rubbery adhesive that can withstand vibration, oil, grease, and extreme temperature variations. It is an excellent adhesive for holding paper, cork, or rubber gaskets
I know that's not what you intended but it's good to keep in mind.
I thought about sealing my windshield frame like this using silicone. I never fold mine down so I might just seal the heck out of it.
We use silicone on everything at the glass shop. It holds up to a lot of stuff and it's got some give to it so it won't crack or rattle loose.