ok i got a head from a 92-95 civic hach not v-tec but it was on a d15b block and on the left side of the head on the intake side there is a port or something that has beed blocked off what is it for???? but i also have a d15b2 head that has the same type of port but it is blocked off but it lookes like it came like that from the factory??? does anyone know whats thats for???