Not as much as you'd think. He moved districts from Riviera Beach (mostly black) to a whiter (and more conservative) district to avoid getting replaced by a liberal black Democrat which is what would have probably happened if he'd stayed in the mostly black district.
actually, West did switch districts but he moved out of a white liberal district, and a white liberal opponent. I do think black voters would vote for West but neither one of the districts had very many black people.