I'm about to put the manifold, flange, and cover over the timing gears. I'm not planning to use a sealant but got to wondering if it would be a good idea. What do you all think? Gaskets are not from Cat.

Several good posts on this you can find under search option. More than I could help with here.

Advance Search “permatex”

Cat sells Permatex hi-tack sealant. or any auto parts store.

depends on the gasket and application. some are better left without,especially if you need to remove in the future.

if you feel the need only do one side if you ever have to take it off that way you have a better chance of not wrecking the gasket.

I think Squatch253 gives some solid advice on this.

It's real simple. If you have to use silicone with a gasket to get it to seal something is wrong and it won't seal anyway! Dry gaskets used will let 2 parts bond as one. Put silicone in the mix and your 2 parts will not bond as one. The silicone will let the 2 parts move separate from each other. I absolutely would not use it on a heavy cast block to a heavy cast timing cover? Silicone works real well on your bathtub!