A community member from Oakley, CA writes:
For those darn valve cover gaskets, go down to the local auto parts store and get windshield adhesive. Next turn the valve covers upside down and glue the gaskets to the valve covers. Install the valve covers onto the heads once the glue has cured. My friend taught me this a while back and it works every time for me...just don't over tighten!
Good tip. Silicone or Permatex adhesive will do the same thing; you can get them at the auto parts store, too.