all you need the proper bolt and nut-- OEM 73~76 @hemi71x has them, i have them, countless other people here probably have them, junkyards have them.
if you don't already have a factory bar to go with your tabbed LCA's then, yeah, i could see going to an aftermarket set up. but even then, i'd swap LCA's for some non-tabbed and sell the 67~72 units to recoup some coin.