Doesnt mention the M715 on that page but it does say:
Splines: In my Spicer books all 67+ axle have 35 splines! Unless they are from a Ford F-350 truck with dual rear wheels. "1967-1975 Ford F-350's dual rear wheels & other" have axle shafts 34414-1 or 35368-1 and thus 23 splined 1.5" axle shaft. One note, they sure have a lot of No-Spins in them.
Ever want to swap in a dually axle....
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!