As far as the wiring goes, since you've had problems, I'd replace your battery cables and ground cables just to make sure you're getting juice to the starter sometimes they can look okay but have lots of resistance under load. It would be even better to use thicker cables. A new solenoid would be a good idea too
You never said how high your compression ratio is, if it's much higher than stock, you may need a high performance geared starter. If so, I'd get it from a company like Summit or Jegs rather than your local parts store.
As far as the freezing water, when you pour water into your radiator, it's going in the engine block too, and after cranking it a bit it's probably most of the way full by now. Your engine may still be okay but you'll want to thaw out the engine in a garage or with a heater and blanket for a few hours. It is possible to crack your block but I doubt that happened. Do you see a hole in your radiator? Water may have just come out the top or popped a hose off.