I installed a rebuilt C-4 out of a 78 or 79 p/u in my 55 this week and it has the perfect arm to hook up to the original rod,it has the arm that comes out in the 9 o clock position and I would think back to 73 should be the same. The pointer in the indicator lines up perfectly and second is in between D and low,I had to bend the rod since I have a Lokar floor mounted gas pedal and a bushing is needed since the arm has a 3/8 hole and the rod is 5/16 and made one from one I got at the hardware store and after I got done found one in a junk drawer. The previous C-4 came out of a 74 van and had a similar arm but was around the 7 o clock position which required the rod to be lengthened about 3 inches so this time I went to the junkyard and grabbed another rod.