rear disk brakes

I did a search for this but didn't find exactly what I needed. I'm looking to put some rear disks on my 91 Roach Coach. It's all stock, and everything I'm seeing in the searches has Dana this, for 8.25 that. I'm not even sure that that stuff is. I just need some better stopping power. More street performance than anything else. Any clues on how to narrow this search down, or some quick help with what to get and do? I'm new to this.

Dana 35 conversion is the same as the Corp 8.25...