not very long at all because the cylinders will start rusting soon
what happens to things that sit in water for a long time?
water pump will sit on engine with lower radiator hose inlet to the left, make sure you dont have a "long water pump", it wont work, 350 is a "short water pump"
4 hours
50 YEARS
It will stay for about how long it takes someone to eat a chicken wings.
The 'spluttering' is not caused by water in the engine but by water on the wires or coils or in the distributor. If you're not talking about a volkswagen, let it idle for about 10 minutes and then let it sit for a few hours (hood closed.) If this is a Volkswagen replace any ignition coils and wires the vehicle uses. Drying will not help. The damage is permanent.
sit it in some hot water
as long as you have not driven the car very long with the water pump bad and overheated the engine, it is fixable. the engine is a noninterference engine so it is not going to hurt the engine if the belt breaks.
Unless you value your corned beef, I wouldn't let it sit in water longer than 10 minutes. It will lose its taste and colour very quickly when exposed in pure (read: unsaltened) water.
between 6-23 seconds
If you let it sit in there for a long time, it will grow roots and will grow. I don't know what it will grow into, but my dad tried doing it once
add bleach to the gas tank and let it sit for 2-3 days. this allows the gas/bleach blend to distill out the water in the lines