/6 K-Frame vs. V8 K

Where is that washer welded on at on the 340 K?

Somewhere on the front middle. It does vary in that area since it appears that it was just tacked on for identification purposes. I have one out back that is out of a 340 car with a sway bar and Kelsey Hayes disc brakes and it has the washer. All of them may not have the washer from what has been said.

Sample pictures.