Autolite 1100 carbs for automatic-tranny cars have a dashpot on the side of the fuel bowl opposite the accelerator pump. It looks and is make a lot like an extra accelerator pump, but instead of shooting fuel into the engine when the throttle is opened, it uses the fuel in it's chamber (controlled release back into the fuel bowl) to delay the throttle's closing.
All it does it delay the last little bit of throttle closing...GM started using them (a little air dashpot that mounted on the intake and contacted the throttle arm directly) when they started using ported vacuum for the distributor advance (early 70's), because the combination of the light load of the auto tranny and the sudden loss of ignition advance was causing the engines to stall and die. On a GM, if you go back to manifold vacuum, you don't need the dashpot. I've had several engines with automatic transmissions that ran just fine without the dashpot.
I have no experience with Ford 6's on this one, but I'd think you could get away without one, unless the SCV-controlled ignition timing needs it. Even then, you might be able to adjust around it by bumping the idle a tad. ???
