ok, how old is ray liotta, probably a lot older than a teenage sonny, and why would we need a young kay? Mikey's gonna be about fifteen probably in the flashback bits, he wouldn't have known kay, and the flashbacks would hardly even focus on him at all as he would have very little to do with the family business at that stage, he's still in school.
"Neri, take a train to Rome. Light a candle for the Archbishop." - Vincenzo Corleone
"But if he betrays me your prayers will not be swift enough to catch him on his way to hell." - Salvatore Guiliano
