Spark plugs for 6C 2500SS
The Alfa owner's manual lists Champion R-17 spark plugs for the 6C 2500SS engine. My engine has a set installed. I am looking for some more of these in case I need them. Apparently they are not common and I cannot find any interchange to another spark plug. These spark plugs are 18mm thread with a 3/4 inch reach. The electrodes are recessed.
Does anyone have different spark plug in their engine? What are you using?