Sealant

Hi all
When doing an engine assembly what sealant is recommended for the internal oil line and other screw in plugs such as oil gallery tubes ends?

I use the Ultra Grey/Black RTV... Which is Oil, Gas resistant and they're good with temps. For the internal oil line I used NPT threads, no sealant was needed, however I didn't use the Heavy Duty thread locker/loctite.

Ok the deal is you need to lubricate the threads until they are sealed. This means a medium of extreme lubricity like teflon tape (most popular)