If you have removed that distributor before and reinstalled it , one more time may be the time you see something you didn't see before and now you have a few more things to look for. If I'm not being too nosey , whose brand of dist cap and rotor have you been using?

Were the replacement dist from a salvage yard or "Rebuilt from auto supply store" ?

 

Rotor was a masterpro first time and I replaced it yesterday with a BWD Select which were the only two options. The Cap honestly I can't say for sure but I believe if memory serves me correct it is either a Motorcraft or BWD Select, Which is a the premium or step up from cheaper ones at store. I do like to use Motorcraft where and when that option is available. But honestly have had good success with BWD and with the success rate of buying the BWD I really can't see my way to pay 2-3x's the price for Motorcraft. As far as the distributor, it was changed at a shop so can't really say where they came from as far as which store but they were "new or rebuilt" not from a salvage yard. Unfortunately with the price of scrap metal finding something for these Bronco 2s around here has become close to impossible. If someone has one they are running it or if they have more the are keeping the extra for spare..... Of course i can't blame them there was a time when I had more than one sitting here and extra parts in the barn.... I may have to take it out again and see ti with a fresh perspective but with the busy week I still got ahead it prob won't happen this week

 

Ok, you've heard my two cents, but let me recapitculate that if you look really hard at the distributor (out of the car is better), and there is ANY shaft play, replace it.
Just becuase they replaced it, doesn't make it any better then the old one. And after all the years in the biz that Hanky has, he's seen defective "new" parts in the box, just like we all have!