Inliners International Forums General Discussion Engines chevy 250 valve cover torque specs

There is no "sucking down tighter as it cools down". The engine is not able to hold the theoretical vacuum that would result from cooling of the internal gasses and fluids. It is not a sealed system. So that part of the ole wives' tale is BS.

And don't let the engine overheat for any reason.

I would recommend a new gasket, check the surfaces for straightness and flatness, and use blue Hylomar or equivalent sealant on both sides. It won't harden, and it can tolerate oil and even gasoline. it just gets tacky.

Hammer the edges of the bolt holes flat, they collapse and cave in with use, especially if retainers are not used to dissipate the load: http://rcmotorcars.com/cart/images/2427%20valve%20cover%20reinf.jpg