9in drum brakes
I had 9" drums on my 1969 Dart (stolen in 1994). The worst problem with them, in my opinion, is the tiny wheel bearings on the 9" spindles. I recall they were Timken SET1 and SET3. The outer bearing on both sides spun the race to ruin the hub and a new hub is a junkyard treasure hunt. In contrast, my 1984 M-B 300D uses SET3 and SET5 wheel bearings, the same as a 1980's Chevy pickup, and even those have required replacing. Perhaps the biggest advantage of the 1973+ setup is that the rotor and hub is integral, so buying a new rotor gets you a new hub. Downside might come when you can no longer source new rotors. I have 9" drums on my 1964 Valiant. No issue since not driving it. If I ever change to disks, I'll probably first swap to 10" spindles and hubs before buying a Scarebird or Wilwood kit because I have 10" parts on-hand.