Hello..new to the forum here...I just got done with building a 5'x3'x2' smoker. Used a 36co3-433 universal gas valve, white Rodgers transformer 120/240, thermotrol temp control (dial type from sausage manuf.), and a cast iron 100,000 btu burner from Tejas smoker. When I built it I broke a cover to allow 2" sides and 3 " top area for insulation. So it's well insulated! Problems I am experiencing 1. Real aggressive (loud WHOOSH) when gas valve turns off at cycle. Doesn't affect anything just annoys me 2. MAIN ISSUE-- Unless I open bottom door smoker runs out of oxygen and burner doesn't burn fully and is real slow to light! I gave an 8" damper in center of bottom door and smoke stack is 4" diameter center of top and 20" long. I feel as though I don't have enough air draw. Just a small FYI too. IF top door is closed fast the flame gets pushed back to orifice. So that is another reason I feel it's too air tight! I was thinking about putting dampers at top front but not sure sizes?? Hate to cut holes without knowing exact flow! That's why aim here to get help! Thank you.