Have you had time to get those pics?? Also the manifold casting numbers. If you made any other modifications please let us know. As for the conical washers, they are designed to distribute the load in a circle around the bolt head. Without the conical washer the bolt head would apply pressure directly to the hole in the manifold increasing the chances of breaking the hole area. A regular flat washer doesn't distribute the load in a circle away from the hole.
If you look closely at the conical washers you'll see that they only contact the manifold along a small area (in a circle) around the hole. When installed correctly there is minimal pressure on the hole itself.
Treblig
