Getting fumes in the cab real bad

My 1968 dart four door is missing a lot of stuff under the dash, but I don't know what belongs there, so I don't know exactly what it is- I know there is supposed to be an outside vent system, with some levers or something that is supposed to let fresh air in? When I go through the car wash, it blows the soapy water right in ! Anyone have a pic or diagram of what is supposed to be there? I am getting pretty bad engine fumes in the cab, and the exhaust system is tight, and I need to fix this ASAP