Ford Racing does in fact make a Traction-Lok unit for 7.5" gears. They're still using 7.5's??? Heh, I didn't know that.
The 7.5" is about the same price as the 8.8" unit, and unless you're using a power adder, I wouldn't bother changing the entire axle. Last I looked a new Traction-Lok cost $229.95 at Summit Racing. They're the only ones I know of to make one for that axle, though. Good luck.
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Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 