how rare are power Brakes ?

My fist car, 71 Duster: rubber floor mat, manual washer motor etc had manual drums but did have p/s and a/t.

My 70 Charger R/T has factory power discs.

My 73 dart came to me with manual drums (10' front, 9" rear) and I just couldn't get used to them. Going from my work van or R/T to the Dart, I never felt confident that I could stop. I scored a new brake booster at Carlisle for $200 from someone who mistakenly bought it for a B body application. I installed it and man, what a difference!!!! I test drove it back to back with my Charger, going down hill 60mph and in a controlled panic stop, and it seemed to stop as just well.

Did check the show cars at Carlisle before my purchase to verify what I was looking for and only saw one with manual drums and a few with pwr disc, Most had manual brakes.