DOHC vs SOHC?

Question

which is more fuel efficient in city or distance driving?

Answer 1

DOHC

Just compare what MPG you get with a BMW, Honda, or Toyota vs something American with a SOHC like a Dodge or older GMs and Fords.

Answer 2

DOHC

Better breathing quicker response and more power on both ends. There is no comparison.

Answer 3

I don't think Chris2EM knows what he's talking about. An Over Head Cam is used to operate the valves directly, with the lobes of the cam,  rather than indirectly with push rods. Some manufacturers use one cam to operate the intakes and another to operate the exhaust valves thus DOHC or Dual Over Head Cam. Some use one cam to operate both intake and exhaust valves thus SOHC. The SOHC will have less reciprocating mass and therefore less drag but who knows which will get better MPG. There are too many other factors which come into play. Most American engines don't use an overhead cam. Rather they use a cam set low which operates the valves through push rods and rocker arms.