Per Leaside aftermarket

For Model 407
42390 Bevel Ring Gear 43 teeth
42391 Drive Pinion And Shaft 11 teeth

For Models E, 407, 611, 614, 618, 670
40558 Bevel Ring Gear 44 teeth
40568 Drive Pinion And Shaft 10 teeth

For Models 614 and 618
40661 Bevel Ring Gear 47 teeth
40189 Drive Pinion And Drive 10 teeth

In the 407 write up in DMAC it gives this info.
The 4.40 gear ratio in the 6-14 was changed to a 3.90 in the new model-407. The 2800 lb standard sedan cruised effortlessly at 50-60 mph.

Where Are You From? Ottawa Ont

Do You own a car built by Durant? Dominion built 1932 614 Sedan