I have a 27 Willys Knight that needs some water pump work. The Willys Overland Knight Registry has most of the factory drawings for Overland, Stearns, Willys Knight, ect. They have 300,000 drawings up to about 1935.
I also have a 1930 Franklin, and the Franklin club has most, of the manufacturing drawings from about 1915 more or less, to the end in 1934. Not quite all, but an impressive amount. Pretty impressive considering they collapsed completely in 1934. I think I have the factory drawing showing how to pin stripe my sedan according to company specs.
As a side note, Willys Overland had a stricter and better drawing standard, Franklin feels more disorganized and a little more off the cuff. They are remarkably beautiful hand drawn assembly drawings that are better than any assembly drawing I have ever done.
The Studebaker Drivers club, or perhaps rather the museum, claims to have the drawings for most Studebaker and Packard from the mid 20s to the end.
I believe the Tucker and the Dusenberg drawings have also survived.
Now that all said, if I remember my history correctly, technically Hudson has had a continuous commercial line from 1909 to today. From Hudson as an idependant->Nash->AMC->Jeep sorta->Chrysler->DaimlerChrysler->whatever that was called and went bankrupt->FiatChrysler. I would expect that at least some of that engineering survived. The drawings would have had commercial value to Nash for a while. Has any of it survived?