OTL the Soviets were pretty restrictive of Jewish emigration, and therefore, it wasn't until it's end that mass Russian emigration to Israel was truly allowed. There was the 70s Aliyah, true, but it wasn't until the 90s that you got true demographic upheaval.
How do you change this and allow this to happen before the 1990s? And how do you direct most of these Jews to Israel rather than the US?
And depending on when this occurs, what regional impacts do you think will happen? Would the settlers movement gain more steam early on post 1967? Would that war even happen?