For what it is worth, I have an old muffler book printed in 1938 that shows the following for the 1929 DA: 5" diameter, 23.5' body length, 26.5" overall length, Inside diameter inlet 2", Inside diameter outlet 1-3/8", inlet and outlet positions in center. Also, this 1938 book lists oval mufflers for the 1936-1938 Dodges.