That's problematic, for a myriad of reasons.
The first problem, is that you say Blacks are assimilated but a different culture.
That's a steep contradiction.
The second problem is this, does a Black kid who has a White neighbor somehow come from a different culture from one another!?
The 3rd problem is that is a Black from rural Mississippi the same culture as a Black from the South Bronx!?
The 4th problem is mixed Black White kids are somehow mixed culture!?
Also, to make matters more complex is that sub culture, A Black & White might be in the nerd social clique, as opposed to the criminal clique somehow makes for a uniform culture!?
Oh really!?
Black kids raised in white upper-class neighborhoods do much better than those in the ghetto. Give them the same opportunities and the gap disappears.