I attended that game at Legion Field in Birmingham. I think history is partly wrong on that. Sam Cunningham did have a big game against Alabama that night. But, I'm almost positive of this: the first black player Wilbur Jackson had already been recruited by the Bear and was on campus playing for the freshman team. Freshman eligibility wasn't adopted until 1972. So, that game didn't really cause the Bear to start recruiting black players.
Something it did speed along was Bryant's moving away from his "skinny little old boys" as linemen. He'd gone for smaller, quicker lineman for years and had teams with few, if any linemen weighing even 200 lbs. They were still smaller than average in that USC game.
Cunningham was about 6' 3" and 230, larger than most Alabama lineman, and that was part of the reason they had such difficulty tackling him that night. He was a big back in 1970 by any measure.
And Alabama defeated USC in LA the following year, and is 6-2 against them overall.
Then, Wilbur Jackson and John Mitchell (a junior college transfer) both played for Alabama in 1971.
I think 71 was the year Bear adopted the Wishbone.