Intake & heads for Dummies

I set my new Eddy perf., non EGR, on to my 360. I noticed something I don't understand. In the center of the heads is a port that I'm pretty sure is a heat cross over of some kind. There is also a "U" shaped port(?) around it. Part of these stickes above the intake manifold. I looked in this area as best I could. It appears to go no where, just down into the head about 3/4".
Help!!!
What the heck it? What does it do?
Head casting numbers are 3671587-9.

Any help would be GREAT!!
Thanks,
Mike


You might feel old if your idea of a road is now going to the Doctors.