I had a 64 Fairlane with a 260 CI and three speed on the column. A few of us were building a “drag” racing car and bought a 289 out of a 63 Fairlane. We took the heads off and realized it was a 260. We needed 3 pistons so we ordered them. They were too big. We went to the Ford dealer and learned that it was a 221. We’d never heard of a 221. The “drag” racer ended up not being very fast.
As I recall, the 221 Windsor engine was not in production for very long.