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.
Far as I know the 1930's have same bodies, 1931 / 32 have the chromed cowl band the 30 didn't. 617 is a sort of half and half Durant, chassis of the 29 but body of the 30.
Where Are You From? Ottawa Ontario Canada
Do You own a car built by Durant? 1932 614 sedan made by Dominion Motors