Abstract: An internal-combustion engine has cylinders 21 arranged preferably in a V-formation with corresponding cylinder heads (27) including connectors for the supply and discharge of fluids. The cylinders are mounted in a crankcase (41) and are supplied with air for combustion by a cast air manifold (51) running the length of the engine, the air manifold being located adjacent to the row of cylinders, preferably in the V. To reduce the amount of pipework the manifold has shaped connectors for at least one of the fluids, in particular the air intake (33) and the water coolant (55), these connectors connecting directly to the relevant connectors on the cylinder head and being pressed against them by the pressure in the manifold.