Radiators: Is 22" enough for 400 HP?

26 wins. Time table loses.
At 403hp you are sitting on a fence between not quite enough power, and having to put up with it. If you are a gearhead, sooner or later, you will be craving more power. With more power comes more heat; and if the 22 gives up, more money.

Straight water is a far superior coolant. In most of N.America we are forced to run antifreeze at certain times of the year.But in terms of sucking the heat out of the engine, straight water does it best.