Actually I have been looking it up and I was right in the first case the ZC is a sohc non vtec with the same specs as a usdm A6(I am at this time confusing myself lol). The D15B and D16A are vtec engines. Give me a day or two and I will list all of the D's that I know of be it USDM, EDM, or JDM

 

My friends zc is a twin cam non vtec same as uk d16a9 crx uk forum says.

 

Bingo.

And Marty, the A6 is the EF SI engine. The first generation SOHC ZC's are basically the same engine, but nobody talks/cares about them because they're damn near impossible to find and pointless to build, so when someone says "SOHC ZC," it tends to mean the 2nd gen VTEC version. The D16A1 is the first 1G Integra engine; DOHC non-VTEC making about 115 hp. While there is an older DOHC ZC that closely resembles it (right down to the brown valve cover), once again, no one really cares about them since they don't bolt right into anything but 3G Civic hatches/1G CRX's. The EDM A8/A9 is the closest cousin to the most common DOHC ZC, which is the 2nd gen.