I am trying to buy an older boat with a 318 Chrysler with wet logs, risers and elbows and you have just raised my blood pressure.... Plan is to replace the whole plant and will def be using the tips provided in your article.
If you have not already, hop on to boatdiesel forum.
You can spend weeks reading/learning of exhaust failures that have taken out more marine diesels then you can count !
Did that today. Only took about 50 suggestions for me to come around..... great place though the format really sucks for a forum. The info is there though.