A safe tune and the ability to monitor all things to catch problems before they become bigger problems is more important here than anything hence that's why I am also in favor of the 8 widebands and want to monitor all of that.

The boat is not a race boat nor a race engine but we want to haul the mail when we want to. Like Mark said we our leaving slices of the pie on the table - one the cam, 2 the compression ratio and 3 Low RPM s, basically for longevity - 4 normal pump gas and 89 octane at that.

This boat is IMO a multi purpose boat meaning --- one day lets tube people around for the day at the lake - the next day its in a poker run and not getting left behind and the next day hey the LOTO shootout is here - run it hard and proud of the results. I think we will have all that covered in a good way.

When we rig boats with stainless exhaust we set them up so they drain water as soon as you shut the key off. Even if the boat is still in the water. The cool water in the headers on shut-off with realitively warm tubes cause tons of condensation like. Add to that upswept exhaust and your putting water on the exhaust valve/ in the cylinders. Not a lot but some. The setup we do bleeds a little water off while running but you are pumping more than enough through the exhaust to keep it cool while running anyhow. We normally use a -4 line for the drain hose. Just some food for thought and if your starting out with a blank hull its relatively easy and pays for itself in the long run.

I'm sorry if I'm missing the obvious, but where do you run the drain to? I very much like the idea of the water draining out at shut down.
Michael

Do you have photos of this system or some idea of where to get the correct parts? I'm guessing you are using a solenoid operated valve of some kind that is normally open and then closes when the key is on? You turn the key off and the valve opens and drains the header down? I definitely like the idea.

For what it's worth, this exhaust will be completely dry to the tip and the tailpipes will have a downswept angle to them............. I can see where condensation can be an issue though.

I run them out the side of the hull. But needs to be above the water line and below the primaries. Gravity in action. This is how I like it best because it's dual purpose. Headers drain as soon as the key goes off and when you start the motor you can take a quick look down the side of the boat and make sure water is pumping. You can also plumb it below that waterline but it will not drain fully until the boat comes out of the water. If you don't want to punch anymore holes in the hull the cover that covers where the factory Merc Bell horn goes works great. Drill it tap it run your lines and your done. But I prefer the dual purpose route...

Pm me your e-mail and I'll get you some pics. All you need is some -4 fittings and hose no fancy electronics.

I understand, you just let it bleed all of the time. My e-mail is: [email protected], no need for PM............. any member can e-mail me at any time.

effective yes but like any water drain system in a marine engine - clearing them out and make sure they drain 100 completely is in the mix as well , especially gravity drains.

Condensation forming on the internal walls of marine exhaust systems has always been a problem hence why the tabulators are installed on OEM stock exhaust set ups -- riser to manifold for Merc - the OEM have known this for years - just saying and just adding info

25-30 psi of water pressure seems to clear them nicely as soon as you hit WOT

I would use Teflon lined hose too......... that isn't going to plug up with much of anything anytime soon. @ BUP -- I can see the value of doing this and it's a simple thing to do.