Allright, I might not be the brightest person out there, but lemme ask this. A Y8 is a better designed head from what I understand, but the compression is higher. If I swap a Y8 instead of my Z6 will I be able to somehow lower the compression back to where it was?

why would you wanna lower the compression of the head when thats the whole point?

it depends man like if you want lower compression just stick with the z6 i mean its the same thing as the y8 just the y8 is better because it has more compression for all motor requirements. so yes its a good swap if you want to.

As I understand the Y8 is less prone to detonation, but the compression is higher. So I was wondering is I could run higher boost with that quality of the Y8 head.

with the slightly higher compression, the slightly lower boost will make the same power. just lower the boost by .5 psi or so.

Ok, now I realize that what I though made no sense...

No worries...

a lot of people lower the compression too much for boost. for them, its usually about bragging numbers, not driving. yeah, a T4 might make some nice hp numbers pushing on a built sohc at 8:1, but most of us would hate driving it every day. youre better off with the higher compression and low boost from the smallest turbo you can get that will flow enough for your motor. it will spool fast and still have good top-end power.

T25...

my thoughts exactly.....