My western sport special dart has the 16 to 1 box and 340 suspension WITHOUT a front sway bar. It was a A body only option and I think only available from 66 to 69.
I later added the front sway bar and poly bushings, and a rear sway bar outa a valiant police package car from 76.
I also think all you had to do was check the proper box when ordering any A body in the right years, and most folks did not.
It goes from 6 turns lock to lock to a tiny bit less then 4 and about doubles the effort to turn the wheels but sure handles and feels nice when driving the car.
I never knew my car was a special 16 to 1 till I test drove a /6 69 with the stock box in it and almost hit a pole when I turned it enough to make the turn as if it was my car...