What is the white sealant used around intake manifold sensors?


What is the white sealant used around the intake manifold sensors? It's also used on the coolant outlet on the 84-85 hot-air intakes. I can't figure out if it's plumber's putty or what. Would a thread sealant work?
Also, anyone know where to get the gasket that goes between the EGR adaptor and the intake manifold for a hot-air... discontinued from GM, go figure! Thinking I may have to just use Ultra-Copper RTV.

Most auotparts stores carry the white sealant. It is called Teflon thread sealer and comes in tape, paste and even a stick now. I use the paste and only need enough to fill a couple of the beginning threads. Once item is threaded in the paste will be absobed in the following threads. Tighten item to spec and you are done. Hope this helps. As far as the EGR, use ultra copper RTV or go to Postons, Full Throttle or any of the other GN restores to get that gasket.
Thanks for the link and the help! Unfortunatly, I already have that gasket. As GM describes the gasket in the 44W book it's the EGR chamber to intake manifold gasket. Part #25515937. This gasket is only found on the hot-airs. Thanks again for your help!