For the S340, at the front you can accomodate a 240mm radiator in push or in pull only. The H80i v2 is a push/pull radiator setups and will not fit in the front albeit with the cable management bar in place. You could either:
a| Mount the H80i v2 at the rear set as exhaust
or
b| Mount the H80i v2 at the front without the cablemanagement bar
or
c| Choose a different case like the Phanteks P400 or the Fractal Define S
though this all depends on your build and your budget ofc.