My car has a leaking heat crossover between the manifold and head which is blocked off by the manifold, ticks after the car warms up a bit as the manifold is still cold and after the manifold warms up it quits ticking, evidently sealing after the manifold expands, the thing drove me crazy trying to find it as I thought it was the rockers as well. Not sure if this would be a problem for you or not though. Matt