Why were there no blacks in the Godfather movie, when the areas in New York are now black?

Not sure, I can only assume they focused on the areas or boroughs that were primarily Italian, seems New York was divided that way during immigration.

The source material by Mario Puzo—and the adaptation by Francis Ford Coppola—depict a world that was, by design and by era, dominated by Italian Americans, often to the explicit exclusion of other ethnic groups, reflecting both the time's realities and prevailing attitudes.

What it too you?

It was about the Italian mafia.

Who says "blacks"?! Is really necessary to remove the word "people" from "black people" when talking about someone with a different skin colour? 💀

Maybe those parts of NYC weren't black at the time.