both are about the same, i beleive the z6 is OBD1, which means it has a chippable ECU, which could be a plus in the future if your lookin to boost. So i say z6 ftw
They are pretty close, but it depends on what you want to do. Generally speaking, the z6 is better for boost and the y8 is supposed to be better for NA apps. The z6 head has tumble ports and the y8 has swirl ports. The y8 also has.4 higher CR then the z6 which is a plus for NA but makes the z6 a tad more boost friendly. The JDM D15B has a better rod/stroke ratio than either which will give you more revs and the head is the best flowing of the 3. It's also ~ 100lbs lighter than it's USDM counterpartsbut you are giving up over 100cc's of displacement.
the D15B head is a exact copy of the Z6 head, both are P08 stamped, both have the same cam in them
Hmm, there is some conjecture about this. I personally have both cams and I can tell just by looking at them that they are not the same cam. Both heads are stamped p08 but does that necessarily mean theyhave the exact same flow characteristics?
I'm not gonna argue with you. It's splitting hairs either way, but I have read several opinions that suggest differences.
z6 or y8?
