intake manifold question

Hey Guys,  I've noticed on some of the oldsmobile intake manifolds, (like my Offenhauser 180) there is a big port at the very back passenger side of the intake...now mine has some pipe fitting in it but what's it for? Is that drilled right thru into the lifter valley and would it be possible to use that for a PCV hook up?

Never mind....I figured it out. Since i don't have a heater in my ride I guess it's a good idea to plug that hole.