Is the rack from a 87 5.0 sport the same as a mustang.
Dimensionally, yes.
Same ratio, maybe.
The rack bushings would be different...but if the Mustang is a 5.0, then yes, it's the same (15:1 ratio). I think the 4-banger 'Stangs still had the 20:1 rack.
Don't they both have 2-piece rack bushings (assuming it is an ~85+ Mustang)?
I once had a steering rack from an '84 XR7 which essentially uses the same K-member as a later Fox Mustang. It had one-piece bushings with the metal sleeve in the center. It's the same way on my '84. The 1986-88 Cougar/T-Bird (and probably Mark VII) use the 2-piece bushings. Sometimes when you buy a new rack it will be packaged with both sets of bushings (I know the Atsco one sold at Auto Zone does) to cover either style of K-member. So the rack itself fits on either K-member, you just have to get the correct bushings. The 2-piece ones are a godsend.
An '84 Mustang (and T-bird) will have a 1-piece rack bushing. An '85-'04 will have a 2-piece bushing.
So the 5.0 sport t-bird rack has the same ratio as a 5.0 mustang.
I installed the Energy Suspension Bushing kit in my 84 Turbo coupe. It had the 2 piece bushing with the metal sleeve stock and that is basicly what E.S. sent with the kit. They did side extras incase you have a lowered, or really lowered car.