Nothing wrong with the 1147cc engine, I have one in my spitfire OK in a bit higher state of tune but a great little engine. there should be a sprung washer between the end cap and the rocker. It looks like the rocker shaft has been rebuilt as all of the pedestals have a recess for a screw originally this was only the rear one, which is not a problem as they are the only ones available now and it makes no difference.