Ede got to it before I could. The main thing to remember is that the factory uses NO sealer on most engine gaskets. The biggest difference between them and us is that they have clean castings and stampings. If you take the time to clean the surfaces completely and thoroughly, you don't need a sealer.
If you want to make sure, a very thin application of a non-hardening sealer can be used. RTV is O.K., and I've used both brush-on and spray-on Permatex Hi-Tack red with good success. I treat all engine bolts that enter the water jeacket with Permatex PST pipe sealant. This is different than regulat teflon pipe thread compound, since it does take a "set" and seals straight threads better. Most pipe joint compounds are intended to be used on tapered pipe threads, with much smaller clearances to fill and seal. There are other brands of head bolt sealers that work just as well and are similar, but I don't know any of the names off the top of my head.
"I'm gonna talk about some freaky sheet now...
" Adobe Acrobat Reader 4.0 KaleCo Auto Parts
[This message has been edited by Vader (edited January 26, 2001).]