Whats the difference between the sohc vtec zc head and the z6 head? is there any? Is there any way to tell the difference between heads?

I got a head the guy said he had a z6 and zc.. I asked for the z6.. put it on my car and it (ef 4 door ex d16a6) and it doesn't feel faster then the y7 head I had on the car previously (a6 head seized)

My friend was laughing at me saying i got a vx head or something. Could this be true? Is there anyway to tell?

I had to modify the dist a lot to get it to fit. Holes wouldn't line up at all had to cut / grind away some of the distributor to get the holes to line up.

It doesn't matter that much to me.. I got the head for practically free.. and its my **** dd anyways. Just would like to know.

 

Are you controlling the VTEC Spool Valve with anything? My guess is no since the other two heads you mentioned were non-VTEC. That is why it is not making power.