Thinking of Doing a LS engine build Maybe sourced from a junkyard. Anyway I think I can marinize using off the shelf parts from company's like indmar or crusader. The thing I have never got a look at on one of their engines is the plumbing. Specifically the thermostat housing. On a SBC the thermostat housing I prefer has outlets that plumb hoses to the bottom of the manifolds and outlets that plumb hoses to the risers.This is using merc dry joint risers. Is there such an animal for a LS motor. I plan to run this through an Alpha Drive utilizing the stock Impeller in the Alpha. Have had great success with the setup and SBC. This seems to be my last hurdle in moving to LS format.

Chris

they are plumbed thru water pump, both connections...intake is dry

I don't know about the specifics of your question but your basic LS engine makes a lot more power than most Merc engines that bolt to an Alpha. You'll likely have pulled the pin on the grenade so to speak on that outdrive.

You can modify the water outlet with a T to run into the bottom of the manifolds, and then use a jumper hose from manifold to riser.
[ATTACH=CONFIG]536589[/ATTACH]

The Thermostat Housing I am talking about has a T on the top of it. The T has 2 check balls connected by a long screw and a spring.. Sort of balances the flow from port to starboard riser to keep temps equal. This is the SBC version but it does not have the T installed on the top. The T goes in the Big hole on top.Like this http://www.michiganmotorz.com/mercru...ons-p-779.html .Not sure how to duplicate this for LS.. Hax that pic is interesting but not sure where the hoses are going to. Where did you get the T.

Chris

I agree Captain. I plan on under propping the boat and taking it easy out of the hole.

The check balls I think are to prevent back filling through those hoses, and to provide a little resistance to direct the majority of the water through the lower hoses. They provide water to cool the exhaust before the thermostat opens. You could make an inline hose adapter, pre thermostat, and attach that same contraption. Any decent radiator shop can make a T like the one in the picture on your factory water pump, run the hoses directly to the water inlet in the bottom of the manifolds, then through the manifolds into the risers and out the exhaust. Run the steam tube from the front of the heads back into the water pump inlet, or out the exhaust, or a thru hull.

I experimented a lot with the merc dry joint exhaust on SBC's. At first I just ran all the water to the bottom of the exhaust manifolds just like the wet joint setup. This always resulted in 1 riser being Very hot and 1 slightly warm regardless of restrictor or non restrictor gaskets. So I changed the thermostat housing to the type with the T on it like merc does on their newer SBS's.. Ran hoses off the t to the risers and main hoses to the bottom of the manifolds. Just like merc. This resulted in Very consistent temps in manifolds and risers on port and starboard sides. So the T and check balls must do something.

Chris