Question: why are dohc better than sohc?
Answer: A SOHC engine with 16 valves produces better torque than a DOHC with the same number of valves due to the DOHC engine additional weight. But the DOHC will produce more horsepower at higher speeds. The SOHC has better low-end torque while the DOHC has more top end power while the two hold the same number of valves.