What you've posted brings up a lot of questions.
Do you want over transom headers or through transom headers?  (The answer to this might bring up additional questions)

We run water to the headers for a couple reasons:  The water helps cut down on the noise level a little.  The water cools the headers a little to preserve the chrome finish (not enough to keep them from burning skin).

Dry headers run very hot and will discolor chrome in one outing, most guys that run dry headers have them jet hot coated or painted.

You will feel an increase in performance by adding headers but, you'll see bigger gains from other up grades (bigger intake, cam, carb...) by having the headers already installed.