Exhaust manifolds are attached to the cylinder head of OHV engines. They are usually made of cast iron or occasionally steel tubing.
 Chevy manifolds
 Rams horn
 Other manifolds
Keeping the bolts tight is the major thing.
If/when the gaskets take a dump, try a set of the foil backed composite gaskets that come in most rebuild gasket sets, if they'll fit the head ports- they will work as good as most any more expensive composite gasket if the bolts are kept tight.
Regardless of what gasket that is used, trim the ID to fit the largest port, be it the header or the head port so there's no overhang into the port. After trimming, start all the bolts and just drop the gaskets into place. Other header gaskets can have the bolt holes slotted in the same way as the foil backed gaskets shown above, for easier installation.
 Ford manifolds