need help to fig out value of a 1972 duster

Hey 66340 welcome back! I dont think the "welded washer" is 100% for sure, my 69 "S" cuda didnt have that on it. Kind of an oddity that washer thing...
If it is a clone, in my opinion if it started life out as a small block versus a /6 makes a difference in the value. A lot easier converting a 318 car to a 340 car and less chance for mistakes.