I’m troubled by the implications of your comment—you seem to be suggesting that no amount of funding increase can bring about racial equality in testing scores. Is that what you meant to suggest?
I used to work as a Night Counselor at a school for boys.
The biggest stumbling block for lower-income students was their utter disdain for higher-learning or any sort of success which wasn't glorified in rap because that and sports figures were the only successes which they were regularly exposed to in popular media --- the gifted student who had gotten the scholarship and escaped the ghetto was not in general going back there to conduct business or practice medicine or teach.
A program where inner city students were required to return to their communities and work to improve them in order to receive their scholarship is about the only way out I can envision.
Parental involvement in education is one of the biggest predictors of educational success. Far, far above funding. The teacher's unions and others just want you to throw more money at the problem