Under wheel well seat belt bracket

Does anyone have a picture or some measurements on where the bracket goes under the rear wheel wells that holds the seat belt buckle in. When I got the my car, these areas were rusted out and the previous owner scabbed in 1/4 inch steel pieces with a bolt through them. Now that the areas are fixed, I made up some of my own brackets but need to place them. I'm not really sure what these are even called. I now have mintubs in the car and the back seat is not in yet. Thanks

1972 Dodge Dart Swinger

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