yea it'll work alot of mustang II's and pintos are trac-locs too, mostly the stick shift cars. your car probably has a 2.79 or 3.00 stock
Pinto, Bobcat, and M2 8" rears have decent gears. The V8 M2s have limited slip standard, however they only have 3.00 gears. The I4 and V6 M2, BC, and Pintos are harder to find with LS, but the gears are 3.40s and 3.55s. I have heard that V6 Bobcats are the best place for 3.40 LS. Pintos didn't have LS as an option, but 3.55 gears were common. To get an LS, you gotta go BC or M2. The tag on the rear will read something like: 3.___55 for an open diff 3.55, or 3.__L__55 for a limited slip 3.55.
all 8" rears are interchangeable. 3.55 should be a good street gear. not the best for 1/4 mile or 1/8 mile racing, but a lot better than what you got now.