Yes, off my 72 the 70 was unique and used a 3 cable system,, the 71,72,73,74 used a 4 cable system. And you're very welcome Apelwaski, and yes the cable is above the exhaust system. I will someday visit France, England and of course Ireland! Maybe take Pat&Drew with me!
(God help us)
I think you can retro fit the 71 up on a 70 as long as you have all the parts and looks like you do. The only difference I can remember offhand is the small curved tab on the bottom of the floorboards on the 70. My 72 doesnt have one but then again it's not needed with the 4 cable system. I could be all wrong about this however!