The bottom line is partial pressure of oxygen. Though cooling the air will increase it, evaporative cooling increases humidity, and the two tend to offset each other.

I don't think evaporative cooling of inlet air would be very effective even if you could come up with a system that worked well. It would be bulky and require constant water addition.

The biggest problem with the 400E is the very tall final drive ratio - 2.29 or thereabouts. Even though it's a fairly large V-8 the tall final drive really saps the performance potential.

Duke