Air injection lines that connect the air pump to the exhaust manifolds. The exhaust manifolds have internal passages that lead to the air injection ports in the heads just below the exhaust ports. These ports in the heads need to be blocked off (easy- 1/4" tap and allen screws) if you're going to run headers or early pre-emissions exhaust manifolds. The tubes and air pump are going to end up in the scrap pile most likely, anyways.