That's one hell of a fan for that tent. 6' x 6' x 6' will be well served by 340 CFM with a big ass filter. There are some variables to work into the equation. Also, your intake needs to be 1.5x your exhaust so a 6" exhaust needs a 9" passive intake.

Check my signature for a link to a discussion thread on grow room setup that includes calculations for sizing your fan needs.