I'm trying to remove an exhaust manifold to put it onto my replacement engine. There is a pipe that goes from the manifold around the backside of the block and reconnects onto something that I think is the flame trap (it's next to the breather box).

I read in the FAQ about the auto tranny filler tube: "The big nut is actually not a nut at all. It is a threaded flange with hex sides. It does not turn. If it turns, you have ruined the pan."

So I loosened the small nut arrowed in the picture, but I still cannot pull it out. My Hayne's only covers through '88 and this is a '90 engine - the manual does not mention this pipe. Also, I checked my '86 car and there is just a sensor with a wire connector in place of where the pipe is on the exhaust manifold. What do I do?

Thanks,
Nate