looks like the counterboring wasn't cleaned up otherwise its the right style spline. Some of the splines look wide and that is probably from the counterbore
The Vendor says also that´s the correct style, they expect a problem with the tailshaft bushing. But they say also the 727 and 518 spline is absolutely the same.............
I did not change the tailshaft bushing, in the donor car there was no problem with the driveshaft etc. Today i get another 727 slip yoke from a friend, will compare these two, maybe i can see a difference.