SIA dubbed it the Stout Scarab III. They confirm the plastic body was built by DuPont. The car was conceived while Stout was a consultant to Graham-Paige, after the latter became part of the Kaiser-Frazier combine.
It was constructed with almost everything fashioned from plastic, including the floor pan/chassis. Built by DuPont engineers, using leftover 'production' Stout Scarab mechanicals, DuPont gave the car to Stout after the project was abandoned. The Stout Family used it regularly, before donating it to the Detroit Historical Museum (where the puzzle picture was taken) in 1951.
Puzzle title changed to "Stout Scarab III" (Not "Project Y", and not "Forty-Six")