Here's what I'm trying to find in this exact shape. It's pretty much for an intake which will allow air to be funneled into the manifold from both sides, a lot like our airbox but hopefully less restrictive since it'll be using 3" pipe. If I need to get 2 silicon elbows and fabricate it somehow I'll do that if I have to.
To direct airflow down I would have to put in a divider possibly with some inlets or holes so I can allow the air to be sucked freely but still have some direction into the intake manifold so the air isn't fighting for space .
If you know what this shape is called, I would assume "Y" then let me know I'm coming up empty on the net.