All I know "for sure" is that the massacre took place in '51 (a little bird told me).
However, the timeline is all over the place no matter which source one uses. Maybe Puzo and FFC conspired to keep us dissecting the novel and th film 40+ years later.
Oli, the reason I did the timeline for the
novel was that the "little bird" in the
film was Sonny's car radio playing the Dodgers/Giants final playoff game in October 1951. My reason for doing the timeline was my belief that the Five Families War couldn't have gone on for nearly five years--thus Michael had to have returned from Sicily way before that. Also, Sonny would have been driving a 10-year-old car when he got whacked.