Here is the correct arrangement with the correct nut and washer. These are correct for the two ends of the exhaust manifold. Take special note of the washer. It has an internal bevel that the castled part of the nut installs into. There are other similar washers, but you must use these on each end of the exhaust manifold. They install as shown.
View attachment 1715996326
View attachment 1715996328
