exhaust gaskets>?

[gmc64sub]

Hello,
I just removed, cleaned up, painted and replaced my exhaust manifolds. I didn't use any gaskets, just a little of the red high temp silicon, on the advice of a diesel mechanic at the local shop. Now I find out I do have a set of the gaskets in my Felpro engine gasket set (hiding under a layer of cardboard)! Should I install the gaskets now while it is relatively easy, or do I need to worry about it? The GM manual and the Diesel Page R&R guide make no mention of this at all.

Thanks for any advice...
Richard

[britannic]

No gaskets or silicon are required (unless the manifold/cylind head is warped), the machining quality is really good and they were designed not to use gaskets.

The manifolds don't expand or contract enough to need additional gas leakage control, unlike gas engines and the venerable Cummins 5.9L, which has been known to crack and break cylinder heads when tuned for higher HP (an ATS 3 piece manifold cures that problem, using leak proof expansion joints).