my old mind and cobwebs are at it again.
way back somewhere in time, i remember a statement saying the bolt holes on the heads were NOT at a 90 degree angle to the sealing surface.
has anyone else heard that ?
i can't remember if that was brought up during a cast valve cover discussion or a gasket sealing discussion.
regardless, if the tin cover is deforming, sealing is going to go away, and more torque applied is going to make it worse.
it is harder to get an "as cast" surface to seal than it is to seal a machined surface.