I need to get a new rear drum for my '67 small block 727 and am finding decent deals on entire drum/planetary assemblies from other transmissions. I still have a 3 pinion planetary so seems like a good time to upgrade.
Would I be safe to drop in an entire 4 pinion planetary + ring gear + drum from a 904 like this?
https://www.ebay.com/itm/304575839320The only difference I can see visually is that this doesn't have the thin splined washer that was in between the planetary and the ring gear on my original.
I have read that there was a change in the spline taper sometime around 1976, but I can't figure out if that would affect what I'm replacing or not.