How fast are you going with a stock planetary

I checked my brain and found I'm partially correct.

There are four planets: 62-65, 66-75, 76-93, 94-up with each having various (3,4,5) numbers of actual planetary gears

There are three splines: 62-75, 76-93, and 94-up

The only factory steel carrier planets I know of are 94-up

I have not found a 94 or later 727. I will check Monday with my parts guru.

There are aftermarket steel planetary assemblies available from A&A or TCS for any of the three splines.

Another thing to consider is make sure the valve body is low band apply. It's a little slower, but you don't have to worry about the sprag. One note about the sprag, The 727 went from a 12 to 14 roller overunning clutch in 88/89. There is an aftermarket 16 roller version, but you have to install a bolt in outer race which requires a drill jig for proper placement.