ZC/ d16z6 difference?

[trace01m]

I keep on seeing the ZC online with D16z6 in perentheses next to it. What is the difference between the two? I mean besides the DOHC being availiable on the ZC.

 

[Steven.]

SOHC ZC Vtec, baiscly just the cam is differnt.
there are also SOHC Non Vtec ZCs, they are simmilar to the A6

and you cant simply put the dohc zc head on the sohc zc blocks.