Please see previous discussion on jumper wire. My signature car has this jumper.
http://www.concoursmustang.com/forum/index.php?topic=14971.msg93273#msg93273
Jeff used the wording " running change" in the other thread.
Reading through that thread reminded me that I need to put back my jumper harness that came with my December-dated Transmission core. I will "assume" (hate that word) that my November car originally had the jumper harness. Easy enough to remove it if further discussion proves otherwise.
I am thinking now about a 30,000 mile coupe that I saw in Fredricksburg a while back. Marty posted pics of it in the unrestored section and I took a few myself...I didn't look at this detail when I saw that car. It was built a couple months prior to mine (thinking September 1966).