Cooling the manifolds

[jet32]

My jetboat is running a 71 Ford Falcon 200,it never had a heat exchanger on it, it was just raw water cooled.I use the boat in saltwater as well so i put a heat exchanger on it(of a mec v8),but now I have to put replace the manifold on it,what I want to no can I run the coolant though the manifold as well.If so is it very hard to set up.Any help would be great thanks