top picture is hole in the side of cooking chamber next is the fire box, then the cooking chamber cooking chamber is 22''x66'' x1/4 fire box is 24''x24''x3/16 pipe between the two is 22''x6''x3/8 it will go half way in to cooking chamber. I have 13'' of 41/2'' thin wall pipe for the stack. i can add up to 6'' more to the stack if needed. Be for I do any more welding what do I need to change? Thanks for any help.