Disc brake master cyl bore size.

What cam, what engine? My 367 had power brakes with a 292/508, as soon as the Rs went up a bit, and stopped the car just fine.They say that cam is around 249@050. I measured mine, and thought it was a little smaller.The original dual-diaphragm had trouble,so I swapped it out for a single off a 73 Dart
If your M/Cs are same size reservoirs, they are for drum/drum. They will work, but you have to check the fluid more often, and as said, It's best to pull the R-valve outta the port to the front discs(usually the rear reservoir).