are these two compatible for boost?

 

Yes.

 

the z6 in going to flow better though it'll have less compression.. typically the optimal stock head for turboing as it lowers your compression, and has pretty good air flow..

the y8 is going to have higher compression but flow a few CFM's less.. in my case where my compression is TOO low, i'll be using this and a mild port to make up the difference..

either way, i would DEFINATELY look into getting a zex 59300 cam for the z6, or a 105300 for the Y8..

 

y8 has alot of quench so watch out for total timing it seems to burn really fast so it will need less timing than most d-series heads.

 

z6 all the way due to the bigger chamber-lower comp. good luck