Learn something new here almost daily.
I was told years ago that the '70-up dual shifter locations was because they used one spot for B-bodies and the other for E-bodies.
Glad I never had occasion to argue that point (especially with my wife).
Tim
They did and it was for both body platforms , but also in a cost cutting operation they moved the crossmember mounting point to the same location as the 727, and 904, so they only needed to build one transmission crossmember.
What Chrysler did at one point late in the 69 model year is start recasting the tailhousing for the upcoming production change and cast a tailhousing with both crossmember mounting locations , but only drilled and tapped the 69 location, but oddly the tailhousing only had the forward shifter mounting point and not the E body rear location.