I'm trying to pinpoint the decade when the CIA allegedly dumped cocaine in black

[karynnj]

3. The 1980s, when Reagan was President is when it happened

It was part of Iran Contra, but not until the Clinton years did the CIA essentially say the Kerry report was correct. Kerry, a then very junior senator, got a SFRC subcommittee that investigated terrorism and international drug running. That committee was one of the earliest to look at the drug and gun running that had started earlier. Kerry became a Senator in 1985 and he started this investigation in 1986. He continued until a plane crash proved the gun running he was investigating, stonewalled by the Regan and later Bush administrations. At that point, Iran Contra became a major scandal and there was a large Congressional investigation that did not include a very junior Senator, though he was called in to question many people who had already lied to his committee. It was for lying to him on his or the big committee that led to indictments of people like Oliver North and Elliot Abrahms. Incidentally GHWB pardoned them at the advice of Bill Barr.

As to the 1960s, I do not think cocaine was the big drug problem.