Reusable b.b. valvecover gaskets

Biggest common problem I see with valve cover sealing issues are where aftermarket intake port runners are a little taller than stock and tend to hold up the top edge of the valve cover from sealing tight. Either grinding the intake runner or notching the valve cover may be needed. That, and not siliconing the gaskets to the covers. Thicker gaskets sometimes work to overcome the taller port runner issues.