Have head question, what is P08-6?
 

This is the number stamped right above the exhaust manifold.

The number B312080434 is stamped near the upper radiator hose outlet.

Basically, I bought this head on ebay and ported it. We put it on the bottom of my 99 ex y8 motor, but I wanna make sure we didnt put a z6 top on...please help!