[hemi43]

Thanks for that! I just wanted to point out where the difference is between the 72-down and 73-up crossmember. On the 73-up, the bracket for the sway bar hold down is sandwiched between the front crossmember and the frame, but on the 72-down, the crossmember is riveted right to the frame and that's why the swaybar hold down brackets don't fit. What I did was notch the brackets (red lines) to clear that area and now use 3 bolts instead of 4.