Hi Senny, got your email thanks, bare with me & I'll email you soon. Jack is pretty much right regarding the manifold cooling.I've had a number of marinised motors & the water jacket is for cooling the exhaust. Boats motors because they are under decks don't have radiaters(no air flow), so cold water(salt or fresh)is pumped through the motor & straight out again constantly. Water jackets("heat exchangers")are fitted to the exhaust as it is the hottest external part of a motor, so keep that cool & your a fair way to keeping your engine cooler. Next time your down at port(wharf) check out the boats (not outboards) & you'll see a small water fountain somewhere while they're running, thats basically the engine coolant pumping out.This brings me to another point, probably like me it never gets cold enough to worry about intake cooling, however exhaust cooling is always a benefit as it helps thermal efficiency(don't panic). Most engine power is converted to & lost through heat & the exhaust system is the biggest culprit. You can get exhaust "wraps" now. So after all that, hook up the water to your manifold but make sure you use corrosion inhibiter in you radiater & check the manifold for corrosion especially if it was used in salt water.
Catch up with you soon.(My brain hurts now)
