1974 base II with a 2.8 v6 sons car. we had it at the shop for a sticker and stalling. Carb is flooding being rebuilt today. On the way back i drove it for safety reasons he is a new driver. Brakes work fine visual inspection mechanic said great shape. The issue I had to stop on a fairly steep hill incline which ever. I had to stand on the brake i mean stand to stop and hold on the hill behind an other car. the feeling was like pushing on a rock pedal. the slightest movement of my foot she would roll and would make a growling sound at the rotors. My thoughts stuck calipers from sitting? I dont think booster no hissing. no bypass on the master cylinder. The other thing i was thinking air. Any help would come at a great time car is down for carb rebuild and can fix want my boy safe. Me to when he is sleeping i can take it on a beat run LOL. Just kidding shes a keeper. Joe