I noticed that Acura still uses SOHC engine on some of their cars. Is there a specific reason why? I've personally talked to an Acura technician about this question but he just said it allows better flow. Not sure what he meant by that?
The big question back at you here is why shouldn't they use SOHC engines? The biggest reason to use them is because DOHC engines are more expensive to produce (which price would get pushed back onto the consumer), there are more moving parts in them (which means they will fail sooner), and they can still do VTEC in either version.
There are other reasons, as well. A SOHC engine is lighter than a DOHC engine because it takes more material in the head to support the DOHC design. The SOHC is also more compact, which leaves more room for design concerns in the engine compartment. This may help supplement hood clearances which can lead to better frontal area of the vehicle, leading to better fuel economy on the road.
The going theory is you can make more power and have better control over the DOHC engine for performance applications, however, if you're talking about basic, right off the showroom floor applications, there's no need to make things more complicated with a DOHC design when you can make the same power/torque with a SOHC design with less cost.