[SCOTI]

Originally Posted by HO455

As far as I can see (And some days it's pretty foggy here) the reasons to swap that haven't been mentioned are.
Going to 73 and up will give you rubber lower control arm bushings which have less NVH than the earlier bronze bushings.
#2 if you have a bad center link it is easier to get a replacement 73 and up version. The 67-72 center links are no longer available new.

Bronze? I thought it was a rubber lined steel sleeve?

As far as the later model bushings being 'better', it depends on what perspective & driving style you have. Earlier bushings are less compliant (increased NVH) vs the 'car-like' later bushings but those car-like bushings deteriorate faster & allow for increased deflection.

78-87 parts are easier to obtain.
Using the 73-87 parts still does not require swapping the main crossmember structure. All that later model stuff can bolt right on to an earlier cross-member.

The only reason I see to swap the cross-member is if the original is suspect (rust/damaged) or you have a fresh/rebuilt/clean different set-up & are swapping the entire assembly of parts as a whole vs. doing things in smaller chunks of time/work effort.