I have a 573  3x2 intake I am installing on my Bird and I found something I need insight on. On the passenger sid of the intake about the location of the E in edlebrock on the underneath side is a threaded hole with a tube sunning to the other side of the intake to an opening next to the E in edlebrock that has a treaded fitting. Does anyone know what this is? Can I plug it or am I supposed to have some line running to it? It seemd to be a vacuum line. Dont know for sure. any insight is appreciated. BTW there isnt a hole on my 553 intake. 

55Birdman  Hickory NC