Yes, the clutch will work fine, but you have to switch out the flywheel. The stock 84 flywheel is 10 inches... So obviously you need a 86-93 10.5 inch flywheel to use the 10.5 clutch. Also, yes... an 88 T-5 will bolt up to your 84 5.0 perfectly, no mods as long as it is a T-5 already.
Nick