That is about par for the course on a new motor. I broke in a new engine for a fellow racer who purchased a Reedy, and even running rich by sound, smoke, and performance his came off at 290, until about the 5th tank around the track, then we were around 275 with better performance. The engine had 8 heat cycles before race day. It will run hot for the first gallon and then once it loosens up, a normal temp is 250-290 for a solid performance tune, depending on fuel and lube package.