If you're spekaing of the large intake manifold fasket between the manifold and the powerhead crankcase, look closely at the gasket. If it is a glossy gasket, you'll probably see a notice on it stating "Use No Sealer". If it's one of the older regular gaskets..... still use no sealer, simply coat it with oil.
Sealer would work its way into various fuel passageways and give you problems galore.