I'm told by Leon that REW (3rd gen) engines are designed to run at around 205 - 210F. He advised not taking the engine above 240 except for short duration, and that oil temps should never regularly go over 250.  266 would be his limit on a really hot day, and only for a short time. 

I certainly value Leon's opinion, but Bruce said not to go over 210, and that's the advice I'll have to follow.    Rest assured, he said it will certainly run OK hotter, but the engine life will be significantly shortened.   Better to fix the cooling problems I think.     

Didn't a rotary airplane have two (count 'em) engine fires because of burst aftermarket oil coolers. If memory serves the owners wife made him sell the rotary and install a Lycoming.  

And if I'm not mistaken, both were in the initial climb, right where Bruce said you'd likely see the highest pressure.