It is possible to remain alive when a living snake bites you.
But there is a great possibility of death, if a dead snake’s detached head bites you.
A snake's detached head can immediately act by reflex and potentially bite.
The induced bite can be just as severe as that of a live snake.
Extra Venom injected
Dead snakes are also incapable of regulating the venom they inject,
so a bite from a dead snake
can often contain large amounts of venom.
Reference - https://en.wikipedia.org/wiki/Snakebite