I got a new long block for my 4.3L merc 1999, should I replace the exhaust manifolds?

[toolman4]

This boat was just used in fresh water and the mainifolds appear in good shape. Also somebody was saying maybe a water pump too?

 

[79Merc80]

Re: I got a new long block for my 4.3L merc 1999, should I replace the exhaust manifo

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