The crossmember is off an earlier car , pre 66 I believe , wit hthe dual bolt trans mount. Your 69 Auto crossmember is what you want to use with the 70 up dual tail mount. The mount location was changed for 1970 so they only had to make one crossmember, instead of 2, and since the tailhousing was being recast for use in e bodies also it made sense to change it instead of the 727 .