my Warhead runs at 250-270 easily. I have the old version and only fill it to 1/2 tank, over 1/2 tank it runs real rich then will lean out as I go below 1/2, but as long as I tune it for 1/2 tank and don't over fill it runs perfectly and easily stays under 270 degrees, I am running the OS#8 plug I would try a OS plug and seal your engine, around the carb body and the pin. also I have cooling holes in my grill, windshield and rear fender, I get no difference with body on or off in temps. I assume you have done the pinch test for your low end needle?? if not run the truck stop and pinch the fuel line near the carb you want it to start to change RPM in around 3-4 seconds, and by 5 die. I have found this is also criticle for the supertiger engine. my engine really screems at 270 degrees at 250 it runs nice.