Heres the one I used. This same seal was used for a lot of different years pretty much from 3/4 tons through 2 tons (single speed axle), from the 40's through the late 60's. National 41130N. Measures - 2.598" x 3.481" x 0.50"
Theres also a felt ring that sits in there, but it doesnt really do much other then keep gunk out. You can reuse it if need be. If your yoke has pitting in it, I have the speedi sleeve number around here somewhere...
Jeff
