im putting a B20 valve cover onto a b18a head, but i dont know wut the extra hole is at the top, can somoene please help me

 

you could use it as a catch can hole if your motor is high comp(built)...

 

and if its not?

 

i did the same and you can put a pvc valve in there and cap it off with a rubber nipple i got at autozone, that hole is there cuz on the new ls motors and b20s there is a line off the intake manifold that goes the to hole. our line goes the the back