Torque converter I.D.

Yes you can tell by the spline count. In both the 727's and 904's there were 2 different spline counts. I'm going by memory so hopefully I'm giving you the right info. The early 904's had 19 splines, later ones had 27 splines. The early 727's had 21 splines, later ones had 24. (I'm sure I'm right about the count on the later ones but the earlier ones are sketchy in my foggy old brain). This is the count of the splines on the smaller shaft in the center. Not the larger outer shaft. I don't know the count of the out shaft right off hand. Never had a reason to check that. BTW: I think it was around 67 or 68 when they changed spline counts. If your not sure on the year of your trans. post the trans. number back here and I'll look it up. The number can be found on the drivers side stamped into the case right above the pan rail.

If I read your post right it looks like they gave you a 727 converter.