Maybe I can add an experience to help others now or in the future. I haven't added much yet.

Center Muffler Pair-Resonators
Mine did not leak they looked good but made a "horrible" in Cabin slapping sound (metallic). Bla bla bla bla slap slap slap on every power stroke, mostly from 600 RPM to 1500 RPM. It would make you feel you had a 2 inch hole in the exhaust system behind the 2 front seats. You could not hear it with the door open sitting in the car. Go figure.

They were original as far as I can tell. MB numbers stamped on them.

Well I had a muffler shop cut them out and put in a 12" straight bypass and I brought them hope to open them up with a chiesel.

First off they were not full of carbon!. They were heavy at 25 pounds but most likely the correct weight.

1. What you have inside is a U tube made of heavy-heavy steel pipe with perforated holes as it was designed. Then about 2/3 the way "outboard" there is a "end-compartment" where they make the bend. At this compartment there is a heavy "partition plate". This plate was rattling and making the noise.

2. The car to me is not any noisier with the center mufflers removed and I suspect it runs alittle better. It sounds slighly Sportier.

If I knew how they were made on the inside instead instead of having them removed I may have "tried" to Peen (bang the **** out of it carefully,lol) the outer cover about 2/3rd the way out with a chiesel to slightly compress the partition plate against the outer metal. I believe it may have worked.

Since this car was from Florida there was no outer rust on the ouside of the muffler.

Hope this helps somebody in the future. Nothing wrong with quick fixxes!

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1982 300SD