a lot of people actually prefer the Z6 head to the Y8, if you look in the intake ports, the Z6 divider is completely vertical and the Y8's is slightly diagonal. the end result is better top end flow from the Z6 and slightly better fuel atomization (and hence, fuel economy) from the Y8 (at the expense of a few HP).

i ran a Z6 head on a Y7 block, but had A6 pistons in there too, and it was a pretty stout motor... so if u have the oppotunity, nab up some A6 pistons, throw them in the Y8 block, drop on your Z6 head, and get it tuned...

you will need wires run for the VTEC solenoid and the knock sensor, and depending on your cars stock IACV, you may need to change from a 3- to 2-wire IACV, but im not sure about the HFs. the computer will have to be a SOHC VTEC ecu, and you will most likely want some type of tuning, i believe the static c/r on the A6 pistons with the Z6 head is somewhere in the 11-11.5:1 range, which means your stock ECU will lean out pretty seriously.

GL with it man.