+1 everything VP wrote. After the floods in Australia I repaired dozens of engine that had been under water, some of them had been stopped with one or more valves open, water and even sand and gravel had washed into the cylinders. Any attempt to start these would have caused terrible damage. Please check before trying to turn over the engine, if in doubt take the cylinder heads off and clean out the crap. Time consuming, but cheaper than an engine rebuild.
Bob