I just replaced my Slick 447 magnetos and harnesses with Bendix. I kept my lightly used harnesses that fit the 447 magnetos. The 447 magneto requires the harness to thread into the magneto cap, they are not part of the cap like the newer ones.
They are blue and have the formed 90* ends at the spark plug end. I don't think they have but 50 hours on them. I had them made when I could not locate ready made harnesses and they are in great condition.
Still have the paperwork also.
If you are interested PM me, I will get the exact hours and the receipt, then you make me an offer that works for you.
If no one here wants them I will put them on e-Bay.