Has anyone tried the cork valve gasket? I know the OEM is the black rubber but I ordered a new set the other day thinking they where OEM but when they came in they where cork, I sent them back and am now looking for the rubber but am starting to second guess myself. I know the valve covers leak on all of these motors so should I switch to cork. It has been used for ever as a valve cover gasket. Also it it completely necesary to replace the bolts? I would imagine if they streched then I could add a washer or two and still be able to torque the down without bottoming out.

 

Yes cork has been used forever, I see know reason why you couldnt use it.
Dont worry aout the bolts for the valve cover, they dont get touqred enough to stretch.