You aren't getting it because you are still running a 16G. I'm not poking fun, and this mod ISN'T for almost everyone, but when you think you need it, you probably do.
Look into most of the 1000+HP builds on EvoM or Tuners/Link etc... Almost all have at least a half filled or a full filled block. In 1/4mile passes, the steel block barely heats up enough to matter. The head still needs coolant however. One of the biggest failures above 900whp is cracking cylinders, hence the need for added strength. Would I try to run it on the street, probably not (even though some guys do) but he isn't building a street car. I "shouldn't" be running aluminum rods on the street, but their performance so far has been amazing. I wouldn't hesitate to do it again.
Back on topic though. If you're dead set on running an electric waterpump, go full fill. I think for your power goals, the simplicity of a half-fill to the bottom of the stock waterpump would be sufficient. You could then get the AN pump outlet and do your cooling system as if it were fairly stock.