The 80 to 82 Fox Tbirds were sometimes unloaded with 3.3 liter and C5. It was amazing it even moved!. They ran the first long wheelbase Fox chassis which morphed out to the 82 Lincoln Mark compact sedan ( crazy like a Fox).
The Aero Bird (also Foxes) from 1983 onwards got the 3.8 instead.
A point worth noting. Foxes never got the 250 because of hood height and compliance issues. In 1981 to 82, there were the 255, 232 and 250 to choose from. The Granada become a Fox somtime in October 1980, and the 250 got axed.
The Fox is the generic term for the modifed strut chassis released in 104.3 or so for the Fairmont, then 100.5, for the Mustang III, and then 108.4 wheelbases for most of the Lincoln luxo barges. The finite element platform was one of the most versitile chassis units, and is still with us today. The Mustang was basically British Cortina sized in width and wheelbase, which was a 4-cyl car. Yet the 1984 Aero LTD II was based on it, and it was huge. A great design, even if it did take 7 years for the engineers to suss out how to stop the axle doing the funky chicken each time you came to a corner.