The Stovebolt Site Forums The Shop Area Engine Shop How to remove exhaust pipe from cast iron collar?

I bought a spare used exhaust manifold for my GMC 302 to replace the cracked one that I have, and it came with the exhaust pipe cut off a few inches from the bottom of the flange. (Its the large port manifold with the 3", 3 bolt outlet and the manual manifold heat valve.) I have the pipe and collar flange from the other manifold, but old flange has been boogered up and the new one is nice.

However, the new one I got has the pipe put into the collar flange with an internal cast iron ferrule that looks pressed in, but the other one I have just sits in there with a flared out section and didn't seal all that well around the pipe. What's the best way to get this ferrule out without destroying it or the flange? The exhaust pipe is thick walled steel and its seized in there good. I soaked it with PB blaster all day and beat on it a bit with an 8 pound hammer, but it only moved a little bit. The ferrule has expanded the pipe enough that it is peening out beyond the collar on both sides of the joint.

Was this connection ever supposed to be taken apart without destroying it? I couldn't get a safe setup in my press without collapsing the pipe in a dangerous manner. It looks like the only other way to remove the collar is to cut the ferrule out.

If it is tight you could always weld you exhaust pipe to it. You say it is several inches long so it would seem possible. Other than than it may have to be milled out if it is as solid as you state.