you're bending the shit out of it...squeezing it for all its worth, you might snap it...but its half dead already by your weight. If you are riding hard packed and/or ice it probably doesn't matter. My son is about your size and he'll ride anything from a 155 to a 166 depending on the snow conditions. However once you start doing purdah you'll want something big enough to float your manly size....btw you don't need a wide. Point is the board also needs to fit the snow conditions and style that you ride.
I'm a downhill longboarder at heart. so my style is carving hard. just riding really.