need to know what sealant to use when building a new motor?

 

Well different parts may require different sealants..
Most gaskets don't require addition sealants and may actually cause leakage issues. On cork or paper gaskets a small amount of gasket adhesive is all that may be required, but on certain gaskets, I would use a little RTV (black) around areas that may contact oil or water.

This is of coarse a generality, and would need more info...