340 exhaust manifold gaskets from the factory: driver side had the heat shield/gasket. Passenger side - no gasket.

Concerning the thick conical washers on 340, there were 4 on the driver side but only 2 on the passenger side. Photos above are the left side showing 4. Photos below are the right side showing only 2, front, middle, rear.

11 Exhaust manifold R front.jpg11 Exhaust manifold R mid.jpg11 Exhaust manifold R rear.jpg

If you don't see two dolphins, you need a vacation.