Abstract: A unit cylinder head for an internal combustion engine, and preferably, a V-diesel engine, is provided with at least one vertical channel on each lateral side face thereof. The channel mates with a corresponding channel provided on an adjacent cylinder head to define a receiving joint for a clamping screw which, thus, straddles two adjacent heads. The intake and exhaust valve seats of the head have the vertical plane joining the axes thereof inclined with respect to the vertical plane along the longitudinal axis of the engine. This permits the exhaust manifold to be short while the inlet manifold has a spiral profile. The lateral faces of the head are formed with openings through which moulding sand is, initially, removed and then are utilized for water circulation.