I am ignorant. My car is old and ratty, but I need it. It was flooded by hurricane Ike - I reckon at least up to the door handles. Though there’s a lot of nasty water inside, what are the chances it could run again and what might that cost (it wont turn over, obviously?).
You would be far ahead most likely in searching for another car. It would take a lot of money and time to restore the car you have now.
Anything is possible but there is no way of knowing. There are going to be a number of problems crop up on it; you can safely bet on that. Suspension parts, electrical, wheel bearings, differentials, are just a couple of real problem areas.
Cougar’s advice is best; it may be time to move on to another car.
Don’t waste your time or your money on a flood car. It will never again be a reliable vehicle, and you should forget it and move on. It would cost less to buy another car than it will cost to repair this swimmer.
The water rose at least to the level of the door handles? And the car is old? As the others have said, the potential problems with this car would make a very long list, and the cost involved for remediating the problems will be very high.
Aside from the expensive mechanical and electrical problems, you will also have problems with mold and mildew growing inside the car, and this is a potential health hazard. All told, this old car is not worth the major expenditure of money that would be necessary to make it driveable and to keep it driveable as components begin to fail.
I am ignorant.
Don’t worry about it, ignorance is simply not having knowledge. Will Rogers correctly stated “Everybody is ignorant, only on different subjects”.
Look for a different ratty car. It’s not worth it. You will be forever beating a dead horse.
A guy I know makes a living at fixing flooded cars. He calls his shop _ _ _'s Submarine repair. His advice to me, when contemplating purchasing one from another source, was that as long as the water didn’t get high enough to get into the dash and the wiring in that neighborhood a flooded car CAN be OK. Those with computers mounted to the floor boards are another matter. I don’t know where you live, but in my area water in a computor is one thing that some insurance companies will designate a car as being NON-REPAIRABLE for. Once that happens, a title CANNOT be obtained for the car. I saw a beautiful '07 Toyota Avalon in that situation a couple of weeks ago. The water had gotten to about two inches up onto the sides of the seats. The car ran, but could not ever be titled again.
All that said, you should probably get another car, one that has not had water that high.
Flooded cars are not always the kiss of death but a lot depends. A friend of mine bought one (submerged over the door handles but an early carbed model) and after a week of tinkering got it ironed out and drove it for 10 years.
My son slid on snow/ice one night and went into a creek with his computerized, fuel injected Ford one night about 10 o’clock. The car was in water over the dashboard for about 2 hours before being pulled out.
So after dumping this off on dad, go figure, it took me about 3 weeks of spare time to get this one going again but it turned out fine.
Seats, carpet, matting, door panels, etc, etc, all came out, various fluids and a 100 other things were replaced/repaired. Monetarily not bad, but time consuming.
If one has to pay somebody to do this stuff then it ain’t worth it. Move on.
(And ignorant does not mean stupid; it only means uninformed and that’s true of all of us.) 
I appreciate all of the responses and info - Thanks.