I have been hunting for photos of the original setup and come up with next to nothing, too. Makes it very difficult for restoration!
I can almost believe that this "backwards" carb is the original setup. I purchased a 1969 4300 carb to put into my car, and I was disappointed to find out that it would not fit in the standard way as the shaft bracket is in the way. There is no way to mount it in the traditional way without moving or removing the shaft and shaft bracket. I didn't think of putting the carb in backwards, but it would probably fit that way in a Mangusta. IF the autolite 4300 is the correct Mangusta carb, I think this is possible.
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