Only thing I know of is the 73 should of had threaded lower ball joints and 74 started using press in lower ball joints. So make sure you have the correct lower ball joints. Also heard the threads can come out when removing the srcew in ball joints on the upper and lower. Mine came out fine but I have heard of issues. Nothing else that I can recall when I did my 73 Charger. BTW, I have a set of nos lower control arm shafts with bushings.