How do you tell the difference between the d16y8 and the z6 heads? cause im bout to buy 1 and dont want to get ripped off and how do you tell if its in good shape besides taking it to a machine shop

 

They are both worth about the same price so no worries about getting "ripped off" on either one. the combustion chambers are different on the two and most likely the easiest way for "you" to tell which is which. The d16z6 quench area is round where the y8 quench area's are more squared looking, just search and you'll find some pics pretty quick explaining all this (and more differences) basically the z6 head flows better at higher RPMs due to the port design where the y8 tends to have higher compression due to the smaller quench area. Typically the z6 head is more sought after than the y8 due to the ports and higher flowing capacity.