A larger engine was built for endurance racing in the mid 1970s . The FVC displaced 1976 c. The FVC produced only 275 b. A larger engine was designed for endurance racing in the mid 1970s , the FVC that displaced 1976 c. The FVC produced only 275 b , down from the 325 h that other twin-cam four cylinders such as the Hart 420S produced but was more reliable .