passenger muffler hanger bracket

Does anyone know if there is a shop that sells a repo passenger muffler hanger bracket . The bracket I am looking for is bolted to the floor. They come on only 340/383 dart, cuda or any a body with factory dual exhaust.
I found a few places that sell one for a a body but they give you lag bolts to attach it. I am looking for the exact replacement .It has the plate with studs on the inside on the floor and the hanger part bolts to the underside. Its crazy they sell this kind for B/E bodies but left out a bodies