Hey guys!

I'm looking to replace my (I think bent) 307 driver's side valve cover. After replacing the valve cover gasket twice with fel pro rubber , a small leak still continues. I've decided to replace the valve cover and run a cork gasket and try my luck with that.

It seems that all aftermarket covers are ten hole, so I figured I'd ask what you guys what you did to seal up those extra 5 holes and keep them sealed up permanently. If I have to pull this valve cover more than one more time I'm gonna pull my hair out

Thanks!!

 

Gasket sealer seems to work well
proper torque on the screws- not too tight.
draw them down evenly.

Form-a-gasket #2
Permatex aviaton goo #3H
Yamabond
gasgacinch

are all good sealers

 

As Chris noted, RTV is your friend. The five-bolt heads have the same gasket surface shape as the 10-bolt heads, including the (undrilled) bosses for all ten valve cover bolts. The 10-bolt covers will seal fine.

Your bigger problem is that 307 valve covers are shaped a little differently than others on top. Using aftermarket covers MAY cause a clearance issue to the HVAC box on your car.

 

I would use cork and RTV the holes or just straight RTV and covering the holes you don't need. I have found RTV or the now discontinued Permadry were only way chrome valve covers didn't leak.

 

If your original intent was to only change the bent valve cover, why not just get another 307 cover in better condition then yours.... They may still be available from any GM dealer if you want a new OEM style.... I purchased three sets a few years ago just to have in my stock....