I'm looking at new exhaust manifolds for my overworked & underappreciated '89 four cylinder that has a crack.
Most of the manifolds for sale are traditional manifolds, but a few have an extra port on the tube coming from the #1 cylinder. What is that port supposed to do?
My manifold has a heat shield with a port in the same location that connects to the air box via a flex hose. It's supposed to route heat from the exhaust manifold to the air box, I think.
Main issue: I want to confirm that I need the traditional manifold, should I buy a new one, not the one with the port in the #1 exhaust tube.
Any advice / education is appreciated.