[joe_padavano]

The exhaust gaskets will not harm anything, just not needed. The flapper and coil on the driver's side manifold is the heat riser valve. The coil is a bimetallic spring and expands as it heats up. When cold, the spring closes the flapper and directs the exhaust through the crossover under the carb and out the other manifold. Once the engine warms up, the spring expands and opens the flapper. This valve often rusts in place, so at a minimim be sure it opens (or is rusted in the open position).