23 spline v 18 spline

Well, it appears that we are both correct...in wierd sorta ways. MotherMopar strikes again.

The 1965 parts book clearly shows that both the trunion and the slip yoke were used, although only the trunion was used in the Dart/Valiant line.

The 68 & 69 parts books support your 18 spline theory, however, the 70 & 71 books only show one 'pinion' for all 833 transmissions and it does not indicate 18 or 23 spline, however, we all know that 23 splines were commonly used in the rest of the cars so there could be an assumption that even the 71-426Hemi had an 18 spline...

...never say never when dealing with old Mopar....