So what i wanted to ask is this... Kozilek, Butcher of Truth goes to graveyard and I have Stonecloaker in hand! My queston is can I exile Kozilek with my Stonecloaker before Kozileks ability resolves ?
Yes you can. Because when Kozilek goes to the graveyard, the "shuffle it into library" goes on the stack. Before that resolves, you can exile it from the graveyard with Stonecloaker.
The "shuffle it into library" is a so called triggered ability, therefore it goes on the stack and you can put your (instant or flash) spells on the stack before resolving that ability.