Ford GT guts is a fancy name for a mustang cobra (gt500) engine. They probably used the T56 from the cobra as well since it is RWD.
The GT 5.4 is all aluminum and uses a dry sump system. The GT motor has a lot of engineering put into it that the Cobras don't. I just read they put a Lightning trans (4R100) in it, which takes the fun out of driving it, IMO. I want to see how they work the GT interior into the Starliner.
Also FYI, terminators used the T56 behind the 4.6. I think they new body styles use a 6000 series Tremec.