Ok I have been debating this.
For this I will assume these things to be true:
1. DOHC allow for more agressive cams (More power)
2. Vtec utalizes cams with 2 profiles one for low rpm economey and torque and a high rpm profile for high end power.
3. SOHC can not have as agressive cam as a dohc because its not able to raise/lower the valves that fast
(DOHC 1 cam per motion intake/exhaust while SOHC 1 cam = exhaust and intake)

So heres my idea on this:
A fully built SOHC ZC motor will have less power or equal to the DOHC Motor. For these reasons:
1. Yes the SOHC ZC Vtec has vtec which allows it to run to profiles.
but
2. The DOHC can run more agressive cams then the SOHC
Result: The DOHC wins becuase it can run <U>more</U> agressive cams and cancelling out the advantage of VTEC.

I dunno i am right,
It sounds though that DOHC's have an advantage of SOHC's

Dave

 

It all depends if you want to go all motor, nitrous, turbo, etc.

A lot of 10 second all motor/ turbo hondas out there run Non VTEC SOHC.

 

Some of your information is incorrect. A single overhead cam engine can run just as crazy of cam profiles as any dual overhead cam engine. The only reason to use the DOHC engine over the SOHC is for the ability to really dial in the cam tuning, and someone with enough financial support can have a cam for an SOHC engine ground with adequate lobe separation angles to completely overcome this advantage. VTEC is always a good thing to have being that it will allow you to optimize the low end, and have a separate cam profile to optimize the high end. My bet would be that given almost any set budget, the SOHC could be built to be more powerful than the DOHC with the same budget.