I know this thread hasn't been updated since 2012 but I got information that I think is relevant to this discussion.
One of the Dodge (FCA) dealership in Quebec City (JD Chrysler de Boischatel) is also a Mopar Service point. So, I contacted them to have their expertise (the Mopar service guys) and the director of their parts department owns a Dodge Dart 1974 like me.
I've asked the following: Knowing that the Dodge Dart 1974 owner's manual mentions "Dexron only" and that Chrysler switched from Dexron to ATF+4 in the 2000's what is Mopar's recommended fluid for a Torqueflite 904/727 ? (I've also mentionned that on some forums, such as this one, people claim that Type F has sharp shifts, that Dexron III destroys the TF or is the fluid of choice... that ATF+4 is superior, etc... lots of contradictory opinions).
His anwser (the original answer in French):
The English traduction:
I've made my own research on that topic and, after gathering all the needed info, will use Dexron-VI (full-synthetic) from licensed manufacturers. (Petro-Canada makes the original product for GM's own AC Delco).
So, look for a Dexron GM License number on the Dexron bottle you buy, you'll be 100% guaranteed the product is compliant with the actual spec, which is fully retrocompatible with previous Dexron specs.