If the fins are all plugged up you would need to remove the IC core and then clean the fins with a degreaser. You still didn't answer if you have the EGR blocked off. If you are still using the EGR with the IC core it will plug up.
Go to your local autozone or what ever you have, and pick up a roll of gasket material. I use the blue roll. Then make your own gasket. One roll is enough to make one gasket. Cost, about $7. Use a thin layer of red RTV to seal it good. Near the snout it is very thin and likes to leak there.
As long as they all line up correctly then they are OK. But gaskets are not your problem here. Because the SC is getting so hot, this indicates to me there is pressure backing up and there fore getting hot. And the IC seems to not be removing the heat because you said the out side of the hose is not hot. You would expect it to be about as hot as the SC.