Cam-in-block
（重定向自Sidevalve）
![Zündapp 9-092 engine. The two camshafts are each driven by the large gears. The vertical tubes contain the pushrods to the rocker arms above the cylinder heads, and thus the overhead valves](/Images/godic/202502/11/Zündapp_Z_9-092_iim_Technikmuseum_Hugo_Junkers_Dessau_2010-08-06_Detail_015608.jpg")
![Engine block of a Ford flathead V8 engine showing the location of the valve ports (the holes above the large cylinder bores)](/Images/godic/202502/11/The_Valve_In_Block_Design_or_Flathead_Block5608.jpg")
![flathead V twin engine, modified for power, depicted on cover of Hot Rod magazine. The](/Images/godic/202502/11/Flathead5608.jpg")
![L-head - Side-valve engine](/Images/godic/202502/11/Side-valve_engine_with_Ricardo's_turbulent_head_015608.png")
The cam-in-block valvetrain layout of piston engines is one where the camshaft is placed within the cylinder block, usually beside and slightly above the crankshaft in a straight engine or directly above the crankshaft in the V of a V engine. This contrasts with an overhead camshaft (OHC) design which places the camshafts within the cylinder head and drives the valves directly or through short rocker arms.