NARROWED REAR OFFSET?
Just got up from the 44 deg F floor (17 deg F outside) under my 1967 Dart with 273.
The rear of transmission tail shaft is ~2" shifted to the passenger side. (~26" CL of transmission to pinch weld under rocker passenger side, ~28" CL of transmission to pinch weld under rocker drivers side)
Engine CL is also ~2" to the passenger side.
That explains why the axles are the same length, shifting the pinion to the passenger side making the CL of Eng, Trans, and Pinion line up correctly.
My measurements were as accurate as I could get with only 8 inches from the bottom of the seam weld to the COLD floor.