I don't want to come accross as any kind of expert on F100/150 brakes but thought I should mention what I do know.
Vintage E and F series vehicles used a large bearing 9, I have one in my garage from a 74 Bronco. If the brakes are for a large bearing 9 they will not fit the small bearing 9 without modification, simple as that.
I drove a 1997 F150 4X4 for many years and it did not even have a 9 under it, I don't know what it was exactly but it looked more like an 11...LOL. Externally it is the same as the one under my current F150, call it a 16-bolt, is absolutely huge. Of course that does necessarilly mean the flanges on the ends of the axle tubes are different. I hope they work for you, be sure and post your findings here.