works fine
recall that there are two shaft/ planataries spline diameters only about .030 difference
the early will not fit on the late shaft- which is good
the late will sloppy fit on the early shaft and strip- which is bad
I do not think there are any 15 degree planataries that will fit without changing the shaft

In my early trans I used the early spline diesel straight cut planateries
They are quiet- I do not understand why they even make helical
later trans you can use the 15 degree planataries or the straight cut diesel
also choices on number of planataries
aluminum vs steel etc
plenty of threads on this around the web
this is also what the high buck re-builders do