The 87 GT is a 4 speed? They are 5 from the factory. If it is a 4 speed, then you just need to swap the tranny. If it was a 5, then get the 4 speed slave, cables, etc. You might even do the whole 85 cradle it it is good.
In a perfect world, cradle out, plunk, cradle back. You might consider driving until it breaks and you have to do it. At least till you tidy up the engine going in.
I would do the clutch while you are there, unless it is new.
[This message has been edited by FieroBUZZ (edited 07-21-2004).]