I would try tightening the bolts first,
if that did not work then replace the exhaust manifold.
if you run it long enough like that, the exhaust gases can cut a groove in the head,
then you will have to replace the exhaust manifold and have the head welded up.
just my two cents
just replaced the exhaust manifold on my TO-35.
not impossible, but it did take some time and effort.
will need all new exhaust manifold nuts, do not use the same nuts!!!!!!!!!!!