I decided to post this after reading the thread about the OS 25.
Mention was made of the anaerobic gasket compound. Check out the photo.
I have been using this compound for the last fifteen years and I have NEVER had a leakage problem.
I've used it on Diesel, glow (up to 30% nitro) and spark (gasoline) engines  and it does have it's place. It can function at 100% strength up to 125 C.
From what I've read, it is not for high temperature applications - use hi-temp silicone for that.
DO NOT use silicone to seal against gasoline - it will break down.
My standard procedure on all of my engines is to remove all paper gaskets and apply the anaerobic compound, allowing as much metal-to-metal contact as possible.

Just my results - yours may vary.

Bob Z.

         Bill, Permatex is the manufacturer its found in most of your local auto parts chain stores. There is quite a bit in that small tube. Ken