K3LA manifold fitting

I recieved my K3’s today and was looking at the center port on the manifold. the threads seem kind of shallow and screwing in anyhing all the way would restrict air flow to the side. what am I missing here?

Your not missing anything mate, thats just the way they are I believe?

The holes u see on the side are for optional air inlet incase you don’t use the bottom. My air enters through the port in the back of the manifold.