That must be a universal arm offered in several different finishes. All seem to be about 14" overall length. I have a black one on order from eBay. Should be here next week.
I have 2 or three metric bolts. and a few coarse thread.
I bought this when I redid mine (Delco alternator)
https://www.amazon.ca/Spectre-Perfo...3&sr=1-1-f7123c3d-6c2e-4dbe-9d7a-6185fb77bc58
I think places like autozone carry it. I was concerned about it being chrome but it looks fine and I beat it up enough (and cut it) installing it.