I am curious about the “freewheeling” effect. I think this was just an effect of having a very high(low numercally) gear ratio, but not really a “slipper clutch” type of effect. I would say that most likely if you were in first gear, you would have the engine braking effect even in overdrive.
At least I don’t remember any slipper clutch like action from the old overdrive trannys.
My old 1955 had a 4.11 rear end.That is one reason it was so quick off the line. That worked just fine in combination with the overdrive.