You might want to look at this thread.
For mine. MT. It happens in the cold. Drives fine. After the first 5 min of driving it stops. There are a couple of opinions as to why.
https://www.bronco6g.com/forum/threads/2-3l-ecoboost-manual-transmission-slight-grind-noise-at-idle.35252/page-4#post-1296807
After I purchased a set in white (nylon/plastic) I was able to get a set of original ‘68 in Chrome.
That said, I have a set of brand new white script. $20 to anyone who wants them. DM me.
I have a 70’s porn meets Lichtenstein thing happening on my 2dr. A buddy of mine is restoring a ‘67 and gave me an extra set of Chrome Script that I added as well. More to come!