My #3 CHT exceeds 400 degrees on every normal takeoff. I have added washer, directed more air over #1 to #3 cylinder, and blocked off airflow through oil cooler. My oil temp is now normal in the 180 to 185 degree range but #3 CHT is still exceeding 400 degrees. I know I can lower the nose and stop the CHT climb, but #3 still climbs to as high as 420 degrees in warm weather. Once I am above about 3000 feet, my CHT is back down below 400 even with full power and then proceeding with a normal climb. I am now considering a cowl flap from Aerosplat. Does anyone have any experience with the new Aerosplat cowl flap and do you think it will help the problem? By the way, I have 1 Lightspeed Electronic and 1 Slick mag and the timing has been checked and adjusted as it should be from Manufacturers specifications!