Have an axle tag, picture below, from...if I recall correctly from 30 years ago...a 70 Mach 1 351C 4 speed staggered shock rear swaybar car.
The WDM-S does not show up on MustangTek, and I don't have a 70 shop manual.
For Fordification web site identifies it as a 9" 3.25 non locking 28 spline.
Perhaps this tag was from another stash - a lot can happen with time and moves.
Can anyone confirm the WDM-S application? Thanks.