273 Exhaust manifold
I will check, but i think my 273 Commando had a gasket in there with those big shields that keep the plug wires off the manifolds. I think it was just a steel shim, but still a gasket. In the attached photo you can see the driver's side guard/gasket between the manifold and plug wires and a matching left (passenger) side that has the gasket but no guard. As far as I know they are NOT reproduced. You can see it in red on the engine pic between the plugs and manifold. (Neither are my pics, but i confirmed that my 66 273 did have this set up when I took it apart.)