First, congrats on installing the EDM-700 monitor. An all-cylinder engine analiizer is inarguably THE best investment an owner can make to monitor and prolong engine life by dealing proactively when things don't look right.... like now. A monitor with the fuel flow option is particularly helpful for troubleshooting from the captured traces upon download, hope you have the FF option.
As to your CHT issue (anything over 400df is WAY too much); since baffling issues and my agreed recommendation to use full power during TO & climb have already been discussed, lets look for some clues within the engine setup, starting with fuel flow (gph). Specifically, during TO & climb at fulll power, what are your EGTs and FF?
By rule of thumb, FF should be rich enough so EGTs settle in the neighborhood of <1300df for adequate internal cooling. Second, and very importantly, do you know for sure that magneto timing is set to spec? Advanced timing causes higher internal cylinder presssure (hence higher CHT). Ironically, an inverse symptom of that condition is lower EGTs. Definately worth checking those things out!