An engine includes exhaust manifold integrally formed with a cylinder head. The engine may include an exhaust manifold having at least one single exhaust outlet for exhausting exhaust gas that is exhausted from at least two cylinders that are not adjacent with each other, wherein periods during which exhaust valves are open are not overlapped with each other between the at least two cylinders.The exhaust manifold is integrally formed with the cylinder head such that costs can be reduced. Also, the water jacket is formed between the exhaust passages of the exhaust manifold such that the durability of the turbocharger that is affected by a heat load can be improved.Also, the twin scroll turbocharger is directly connected to the exhaust outlet of the manifold such that the compression ratio of the intake air can be effectively improved. Further, the exhaust passages at which pulsation interference occurs with each other are separately disposed and the exhaust passages at which pulsation interference does not occur are combined together to form a single passage such that the torque is improved at low rpm and the remaining gas is effectively scavenged.