Now that Doug responded we've got the story. I remember seeing ( and photographing) the car at POR 76. The car got a lot of attention from the legions of Datsun drivers. It was a red 4-door sedan. It was said to have a U20 ( Datsun SRL311 engine) and 5 speed transmission. It did not have the then relatively new ( and rare) L20B. Doug confirmed the 5 speed part . The high performance Datsun bible of the time did have a story about the BRE Desert car and I remember a U20 engine there. It was not at the event as a competition vehicle . Doug may chose to confirm/deny/ignore the rest of the story.
Doug was clerk of the course. In the process of the final check, the car broke down stranding the crew in the middle of the woods. They broke into a nearby cabin to spend the night- this was early November in the UP- and were rescued the next day. Or so the story goes.
The was a second-later RHD 510 in Michigan rally. Somehow a real 510 SSS ending up on a used car lot in Grand Rapids in the mid-seventies. It was from South Africa ,RHD, and a bitch to sell. Don Fetrow, a longtime Furrin Group member bought it cheaply and used it as a street car for a number of years. He sold it to one of the Traverse City rally group who converted it into a rally car. It only ran one or two rallies before centerpunching a tree. It was parted out but I had heard that the RHD pieces were saved for a future project.
Those are my stories and I'm sticking to them.