It is turbo spline, but most people I know run turbo spline converters in their powerglide. You just need a turbo spline shaft. The tranny in my race truck has a turbo spline converter and my dragster has a glide spline. If you dont need it, its no big deal I was just throwin it out there...
You can check out transmission specialties converters at
http://transmission-specialties.com/...a1ba1a312770fe
They can be bought for a fair price and are pretty good quality.