Only in the North. Southern Blacks (those that could vote) didn’t fully go to the dark side until 1964.
Although I did get into some local voting a lot of years ago I was meaning the black vote for president, in 1936 the blacks did a complete reverse from Republican to Democrat.
In 1932 FDR won the typical Dem portion of the black vote with 23%, in 1936 that historical voting pattern permanently reversed with 71% of the black vote going for FDR and they never looked back.
Black party registration lagged some but it caught up quickly enough.
Interestingly LBJ got a record (before Obama) 94% of the black vote, before the legislation he was talking about.