Bill,
What is your Lucas wiper motor, or more importantly, the transmission from?
If they are from British cars with the small knurled head, then I don't have an answer for you. If you got it from a Saab, then a standard replacement arm will work. I got mine from NAPA also but it was a Trico generic replacement arm. (I welded a spray bar on it, so I wanted something inexpensive in case I hosed it up.)
BTW, I used never-seize on my cable.
Lynn