Yes, As 55Tractor states you need an exhaust on the vehicle to tune. The back pressure from an exhaust will effect the how your carb is tuned. Tune it the way you are going to run it (in relation to your exhaust) otherwise you are wasting time.
Yes, blowing black smoke is running too rich. Black sooty plugs is running too rich. If you are running rich on an open header, I would assume that it will be rich when you get an exhaust on it too.
