Monday, my wife and I took the day off and drove the 56 to the coast over some low mountains to Half Moon Bay, down the coast to Santa Cruz, back up the mountains and back home. First trip with any meat on it, 160 miles and 2600 feet in elevation. The whole trip went great but there was a clicking noise from the engine. Noises make me nervous and before we left I had tightened the exhaust manifold bolts. This did not solve the problem. The next day I pulled the valve cover (left side) and all the rockers were oiling fine and I used the stethoscope and could not locate the source. During the drive, the noise went away during deceleration and I suspected an exhaust leak. Today replaced exhaust maifold gaskets and clicking gone. I feel a big relief.