In short, that could quite possibly be the biggest fan overkill I've seen short of that one PC that was basically in a case MADE of fans.
I run a 932 case and couldn't be happier with the airflow. The fans are large, slow and quiet and move an incredible amount of air.
On top of it, you're talking about boosting a 970 to 3.33ghz, which is essentially the 980X stock speed... that's boosting it like 120mhz... I assume that's just an initial goal- but even taking it to 4.3+ will not require you to stuff every fan you can find at "Fan Warehouse" into the poor HAF. It is, in fact, called HAF for a reason, you know. Or perhaps you don't? Anyway, HAF stands for "High Air Flow." And it performs exactly as advertised so if I can say anything about this and help you out- spend the money elsewhere.