Dirk,
You shouldn't be concerned about 225* I have an iron head 460 in my West Coast. I run a 190* T-stat and twin 900 CFM pusher fans on a T-stat. I have the fans set to come on at 240* and as soon as they come on, which is only in traffic, the temp comes down to 210*-220*. The fans never run when I'm moving faster than 30MPH. Cruising on the freeway on a 75* day she will run about 200* to 220* depending on how hard I'm running. You must remember that a 50/50 mix of
antifreeze and water with a 15 lb cap will raise the boiling point to 265*, and a 70/30 mix, which is what I run, won't boil till 276*. These numbers come right off the Prestone jug. I have always run all of my engines hot. They make more power, run cleaner and last longer than running them too cool.
I'm sure there will be many that strongly disagree with me on this, including some engine builders, but I have over 35 years and many engine tear downs that prove to me it's good to run them hot.
If you want some interesting reading, do a search for "Smokey Yunick Adiabatic Engine"
Ray