Good luck with that one. Your best bet is to try to find someone parting out a car with that stuff in it. Ill keep an eye out, in fact I might have a 73 parts car in the next few weeks. Ill let you know if it happens. Getting the car is easy, storing it for dismantling is the problem.
I would greatly appreciate it. This guy in Minnesota had a set and his mechanic snapped both pieces while removing them and he would not budge on the price he was asking...
Was going to suggest the same as GXR. Of course you can also find them on eBay if you're willing to pay an arm and a leg. These pieces in tact are the white whales of restoring Machs.