re: Betty, the formidable V8 | 1:3 V8 engine scale model build We continue the build; attaching the lower cylinder heads onto the cylinder block. Ensuring everything has the correct orientation. The cylinder head have numbers imprinted on them, 1 to 4 and 5 to 8. Onto the cam shafts. There are two cam shaft (those metal rods that were also used to hold the valve springs together prior assembly) and there are 16 cams!. You can see on the drawing that the shaft has a flat side to it, each cam has an unique orientation on the shaft. So each cam (or rather pair) has an unique letter to identify it. And they must be slid on the shaft in a particular order. This will ensure that each valves opens and closes at the correct time.