I first took temp readings with the smoker out of the box. I was only cooking, not smoking and got lid gauge up to 405 F. Meat level temp was 340 F with seperate probe. The two temps never got closer than 50F throughout the heat up. I then had the custom chimmney extension made up (see pics). I got the temp up to 270 F and the meat level was 255 F. Throughout the range the temps only varied 10 to 15 degrees, alot better then 65 degrees as before. The extension I made only takes a 3 1/2" circle of area away from the smoking surface. The elbow is easily removed and is attached with a split tin soup can. I made a painful discovery with the Cimarron, the handle to the firebox dampner gets really HOT. I drilled out a small wood chunk and slipped it over the handle, way cooler! I hope this helps out fellow Cimarron owners. John C.