It's pretty clever, actually. The exhaust manifold floats on the head. The 2 end studs clamp only one part of the manifold. All the others clamp two manifolds with their special washers. So in order to lessen the clamping force on the 2 outer studs, Chrysler made special nuts and special brass washers. The washers have a countersink. The nuts have an almost matching taper. The nuts are slit on the taper side. These slits create fingers. As the nuts are tightened down the fingers squeeze the threads and limit the clamping force on the manifold. This allows all the nuts to be tightened to the same torque.
