Hit a bit of a puzzle today while trying to replace the exhaust header on my 78 240D. I finally got the old one off but noticed its end is sort of flared inward, while the new one flares outward. The pipe that comes off the manifold seems to be flared outward as well, so something isn't right with the new pipe. At first I thought the old one had a gasket that was so rusted in it looked like part of the old pipe, but the EPC does not show any gasket, and when I did a search here other threads confirmed there isn't one.
So ... did the dealership accidentally order me the wrong pipe? Or is there in fact a gasket on some models that should go between them? I have the flange and nuts, but I can't imagine it's going to form a seal with an outward-flared end connected to an outward-flared end. I can go take pictures if needed. I can't imagine I'll ever find the receipt for the part I have, bought it ages ago.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)