I put the firebox under the cook chamber for a more even heat. It's 2/12 inch pipe ( with dampers that I built( probably could have went a lil bigger) put wood cabinet knobs on the shafts with springs under them for a lil resistance. I'm also gonna change how the cook chamber opens and put two slide out racks. Runs about 250 with a small fire and dampers wide open. First cook was St. Louis ribs that turned out great