Read the following passage carefully and fill in each blank with a proper word from the list however smaller poworful exhaust center so that located valves supports performance In the past, most engines had two ( 1) for each cylinder, one is for the intake and the other for the (2 ). Nowadays, (3 ), many smaller and high ( 4) engines use two intake valves and two exhaust valves per cylinder. This design makes smaller engines more ( 5). The exhaust valves are usually (6 ) in diameter than the intake ones. The valves are (7 ) within the cylinder head on most engines designed today. The valve guide is the hole that ( 8) the valve in the cylinder head. It helps to hold and( 9) the valve ( 10) correct seating can be obtained.