olds 455 question

[NautiII]

I currently have a fitting coming out of the manifold that leads to a t, then to the headers. I have seen mostly another type, that actually has two water outlets. one overboard, one to the headers. does this make sense? hope so. what is the difference? hope this isnt a stupid question!

[Moneypitt]

If you run just the T to the headers you will have too much water in the tubes. Some systems also run another exit through the headers at the back, or just overboard like you mentioned. IMO, using just the T will not allow enough water through the engine to maintain cooling. Rig up another "dump" hose or 2 and send it overboard. I put hoses out the back, which I now wish were out the side near the driver so I could monitor the water temp with my hand as it leaves the boat. I also found that even 2 dump hoses were not enough to reduce flow through the headers, so I put reducers in the fitting as it splits to the little tubes. There is a fine line between enough water and too much as the RPMs change and the pump pressure comes up...........MP

[Aluminum Squirt]

This is no answer to your original question, but I agree with MP about the side dumps. I put a dump out the side right behind my seat, that way I can reach over and feel how warm the water is and how much is flowing. Through dumb (dump??) luck, as the pressure (and speed) get higher, the flow pretty much shoots straight out the side so I can see it out of the corner of my eye with a slight turn of the head, even with a helmet on. Helps to let me know that at the very least I've got water flow-Aluminum Squirt