That's an excellent question. Unfortunately, I know very little about brake systems, so I don't know. I'm like you. I'd like to know how to improve the brakes and stopping power of my Bronco, cuz the few times I could get it to run, it was scary trying to stop it!!
Anyway, the article at that Ford-truck.com website claims that the OEM 11" vacuum booster (forgive my braking ignorance, but is that the same thing as a brake booster?) on a 78-79 Bronco is to weak in pressurizing the hydraulic system. I don't know if the later Broncos use the same booster as the 78-79 Broncos do, but the braking power on my 86 Bronco is extremely weak, so I assume that they probably do use the same brake booster. The article goes on to claim that a 79 F350 dual diaphram booster provides twice the power output. It then says that an F350 master cylinder is needed because the stock one has a narrower bolt pattern and will not fit the F350 booster. It also says that it has a bigger bore, but I'll admit I did not really understand the physics explanation on volume and pressure necessitating bigger calipers that should be used with a bigger master cylinder. Hopefully someone with more knowledge and experience with brake systems will post and educate me some more on that!!