Valve Cover Gaskets

str12-340 said
There is just too much run between bolts to use silicon only for a gasket that narrow. I guess that's why Mopar and Milodon used a steel core covered with silicon for valve cover gaskets

I think they have a version that has the metal inside too IIRC

I think the biggest issue is clean dry and little torque.

But like I said I have not tried them yet.