I had 2 Corvairs Corsas (140 and 180). Drum brakes stopped fine but they are difficult to adjust so all 4 stop the same without pulling. But that isn't a knock on the car but rather drum brakes.Al, I don't disagree with your opinion that the cars didn't have brakes to match the performance but would ask you how many 60s domestic production cars had really good brakes? Not too many of them in my experience.
I also wonder if your 'Vair didn't have some problem with the brakes, as these cars are not noted for having particularly poor brakes. The rear weight bias helps braking performance a bit (by helping to prevent rear lockup under hard braking).