Check out Chilton's Automotive Multiguide (spring 1931) for interchanges. These were reproduced in a large quanity several years ago are are easily available (usually about 10-20 bucks). The lower cowl sections will most often be rusted in all our cars where the wooden sill members are bolted/nailed. I had to remake these areas on my car and weld in sections. No interchanges with anything except other Durants, which doesn't help one bit.