I read a story in the 1980's (before 1984) about a future where race (black, white, etc.) had disappeared and for some reason "they" were attempting to bring back the races. The main character was a white boy. At the beginning of the story he meets a girl of another race that is also part of the project to bring back distinct races.
I thought the title was "killing time" but that really does not fit with the story I remember and none of the books I have found with that title fit.
The other detail I remember is that the people counted in octal (base 8) which I thought was cool.