rear brake choices

What are my options for rear brakes? I bought an empty A body 8 3/4 axle housing and a complete 489 chunk as separate units, basically will build a rear end from parts. Now on to axles and brakes etc.

What do I look for(backing plates etc) if I wanted discs and what if I have to settle for drums? I see there are several diameters and widths?(if i read right) of drums, bigger is better I guess but what if any fitment probs might I run into? If discs are very costly is it really worth it for a street car or will big drums be OK? What's the interchange of brake parts with say b body 8 3/4 ? same brake parts?

1966 Dart, 392 hemi, 727

Many thanks