I would run a dura spark dist. from a 85 Mustang GT with a 5.0 and a four barrel carb. If you are running a roller cam then you are all good just drop it in but if you are running a flat tappet cam you will need to swap out this dist. drive gear. You can run a blue dura spark box or a MSD box and then you will be all good. It super easy to wire up and get it going to.
Why would you buy an 85 Stang distributor, then swap the steel gear off it, when 99.99% of the other Duraspark applications used an iron gear ?