Well better late etc. I also have an early model S7 which was finished in 2007 and have gotten 1500 hours on it. Most fun airplane I have ever had.
I was about to get my third old model brass radiator to replace the leaky one when I read Dave's great article about retrofitting the new Kitfox radiator. The results have been phenomenal. I had already switched to 50/50 because of my water temps were running close to 240 degrees. Even then on a 70 deg OAT day I would be over 220 and rising. The CHT's were also high. My water temp is now running 20 to 25 degrees lower and so are the CHT's for all the combinations of OAT/RPM I have tried.
Thanks again Dave..
Rich Little