Had to be the brakes... my high school car was a 65 goat. One day when I was coming home I hit the brakes and nothing... to the floor the pedal went. Luckily I was pulling into the yard and had plenty of room. When I checked under the hood the clutch linkage had rubbed against the brake line and rubbed a hole. And since 65 GTOs have single reservoir master cylinders I had no brakes.