Add some ideas about air inlets and outlets.... and what you are planning on heating it with... etc.... we'll fix you up....
I really have no idea, I've never done this before. I guess I was thinking of going with three 1" ball valves plus maybe a 3" pipe and damper for air inlets. From there I'd go with a 14"x 24"h fuel basket. Heat it with lump charcoal, although if wood is possible I'd go strictly wood, or mix. Never tried briquettes, not sure about the flavour.Add some ideas about air inlets and outlets.... and what you are planning on heating it with... etc.... we'll fix you up....
Probably 1 ea 3/4" ball valve and 2 ea 3/4" nipples with caps.... and for the exhaust, holes around the top edge of the barrel... that way, water won't drip in and on the food... some folks have used corks to plug the exh. holes....
About the inlets.... if you need more air than the 1 ball valve will allow, pull off one pipe cap and adjust the ball valve.. more air, remove the next pipe cap... that saves on ball valves...
I've never been a fan of exhaust out the top.... condensate drips on food... built my first that way and that was my last.....
If I were to try this... I think I would make doors in it as you won't be able to reach down in it as stated above... if you were to use wood, you would need an access door to the fire pit to add more wood... one load, I don't believe would last the length of a cook... JMO ...
I made my first brisket and I mean first one ever, and damn was it dry.