Time to take off the manifolds to fix that exhaust gas leakage. Find out that the exhaust gasket between the intake and exhaust was gone. Also have to fix a threat in the ex manifold it was broken for years. But I have notice a crack in the exhaust manifold. See this is a common problem on the /6 manifold. I want to try to repair this before getting something different for exhaust. I saw that is likely possible to weld the cast iron manifold with fillers. Can try this to weld with TIG and fill the manifold with sand to keep the heat and to and ensuring that it cools down as well as possible. Also it is an possibility to fill up the crack with JB weld. I do doubt which method delivers the best results. Thanks!