HELP- How can I tell if 727 is SB or BB?

This thread, from B bodies

Your 'Guide' to the 727/904 transmission

And from bangshift





and if they are "unknown" don't forget the oddities, IHC/ AMC and I don't remember what all else. They made some sort of torqueflite for the US Postal American General "Jeeps" I think they bolted to an iron duke