700r4 spline count

[79 surfwagon]

Which splines am i supposed to count to determine if I have a 27 spline 700r4 or 30 spline? The case id number says its a 1984 unit, but I count the small diameter shaft where the converter goes and it has 30. I count the big diameter shaft that is around the smaller shaft and it has 27. I need to know if it's a 27 or 30 so I can get the right converter. It has been rebuilt before, so i don't know if it's been upgraded to the 30 spline shaft.

Thanks for your help!!!

 

[79 surfwagon]

I found the answer! TCI tech says to count the shaft you can spin by hand (the narrower of the two shafts). In my case, this is a 30 spline transmission. I hope this helps someone else who might be doing a 700r4.