some will die. most will not receive enough nutrition since there is so much compitition for food. the few that do ok will kill others for their shells. the response will be, "well there was 160 so you have to figure some won't make it." the truth is it was too many to begin with.
1 or less per 10 gallons is a better rule of thumb. i would go w/ 18 hermits and 18 snails, 36 in all. 40 to round it is that's easier for purchasing, but this guy is about 300% too stocked.