FYI: There were 3 speed automatics in vehicles made until 1991 (727 torqueflite for instance in Wagoneers, HD Dodge Diesels, etc) and later for heavier duty commercial vehicle applications. People still use things like TH400s, C4s and 727a/bs for higher HP drag vehicles to this day. Even the 2-speed 'glide is still a popular choice even though the cases are getting harder and harder to find.

I'm no expert but I did learn from some of the best in the business. Transmission ignorance is one of my pet peeves.