Waaay too much reading in Swedish references with no absolute answer.
How about Olle Schjolin, a Swedish American hired by Volvo after a successful career with GM and Opel designing cars in the 1930's.
He was responsible for the design of the Volvo PV60, which looked a lot like a 1939 Pontiac and the 830 series was also very "American" looking so maybe he had a hand in the 830 design as well.
Bill