Correctly viewed, a pushrod engine's valvetrain assembly stands at the gateway of improved power. It is not a collection of components only intended to time and provide the correct valve motion.

Cam or lifter problem explained diagnosing valvetrain issues and understanding common engine performance symptoms #Camshaft ...

Desmodromic valvetrains allow for higher revs without needing to worry about valve float. So why do automakers not often use them outside of motorcycles?