The thing that goes from the rotating arm to the cable is called the 
"clutch hook."  And apparently they're quite specific to the model year, 
and even the serial ##.  The logic of this will become apparent when you 
get to the parts yard.  For the 1970, there are 3 different ones, of 
differing slants/hole location, etc.  

Mine broke (long story, re:  the proper clutch 
plate/t/o bearing) and I finally managed a parts yard one--apparently 
they don't break often, so the yard might be your best bet.  And bring 
your old one (!).  ;-|

Good luck!

JKH--New Mexico