The '69 rear is 55" flange to flange with leaf center @44" (62-70).
'71 wagon would have been a 59.2" & leaf @47.3"
Another choice would be a 9 1/4 rear from a B or C-Body. These have the same mounting specs as the wagon. Driveline will probably need altering.
As stated above, the E-Body will...