Valve Cover Gaskets - Cork or Rubber

I looking to replace valve cover gasket on my 1985 S-10 Blazer. It appear to be leaking some oil on the rear side (on the driver side). Which valve cover gaskets are better to use cork or rubber? Also, Do anyone have any good tips when replacing such hand tight bolts or using a minium dab of RTV sealant on both sides.

I prefer rubberized gaskets and you should only need a dab of RTV to stick them to the covers as an installation aid.

My opinion anyway is that cork is inferior to what it used to be but I have no idea why unless is has something to with changes in the growing process, the grade used, etc. It may even be synthetic cork as far as I know.

With the valve covers off check the bolt holes and make sure they’re not dimpled down. If so, tap them back up. It’s not a bad idea to go back in a few days and snug the cover bolts back up. After the gaskets have a few days to relax the bolts will often loosen a bit.