And sometimes even the big name springs break. This is a dual PAC spring that failed in my FE. The main spring broke into 3 pieces. The smaller spring held the valve in place. The valve train was well maintained. The spring had about 2800 miles on it. It is listed in the PAC catalog as a spring designed for high rpm use in circle track racing. Its use in my engine was 100% street driven with an occasional high rpm spurt.
