Paul, it's no wonder to me that it would you who should eventually find these informations.
You' re right about it all of course, except maybe that in my source Charles Mann, from Elkhart, Indiana, is only noted as the "previous owner". It doesn't say that he's the man who built it. The engine that equipped this car when built is not known.
So, if you agree, we'll attribute the car to this mysterious "Studebaker engineer".
as I said before, one point for metalshapes and one for you.