The Gaskets are like the mortar holding bricks on a building. The Engine Gaskets on a Daihatsu Hijet are what holds the parts of the engine together sealing the internals to keep engine compression so the engine can function at it peek performance. The Intake gasket holds the intake manifold to the cylinder head. The exhaust gasket holds the Exhaust manifold to the cylinder head. The valve cover gasket  or Rocker Cover Gasket holds the cover to the cylinder head and keeps the engine oil inside the engine. The cylinder head gasket holds the engine cylinder head to the engine block keeping compression up.