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Head Janitor
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Discussion Starter #1
Well…it’s finally done (mostly). All I have left to do is pressure test some the fresh water connections and put the back seat in.

Specs:
21’ Liberator with Dominator pump
383 LS1
238/244 Hyd. Roller
MTI Stg 3 241 Cast Heads
Yella Terra Rockers
Rewarder Water Injected Through Transom Headers
Edelbrock Performer Intake
850 Carb
MSD 6LS
Closed Cooling System














 

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Head Janitor
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Discussion Starter #3
Nice job is there a reason you went closed cooling?
Thanks!

and yeah, there are several reasons I went with semi closed cooling...

1) At the time of the first LS1 swap, I would've had to fab the water ports to use open cooling - and I work construction on the road and didn't know/trust any fabricators in the area I was in. Now several companies (like Moroso) make these ports and it wouldn't be an issue now.

2) I know now that there are inline t-stats, but I didn't really know that then - and a "cold" running LS1 isn't good. Since the t-stat on an LS1 is in the water pump housing, I just thought it'd be easier to keep it.

3) I got a GREAT deal on the heat exchanger. I actually bought a pair of heat exhangers for $75.

4) Some of the lakes I go to have brine water - brine water + aluminum really isn't that good.

5) Winterizing is a breeze!

6) If I put this engine back in a car at some point, I don't have to worry about mud/rocks/other trash being in the engine just waiting to plug my radiator or heater core.
 

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I went open with mine but I only boat in the Colorado river. I made motorplates out of 3/8" aluminum and tapped it directly for 1/2" NPT for my water lines. I'm very anxious to see how your setup performs. Can't wait to see one of these in a gullwing
 

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Head Janitor
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Discussion Starter #5
I went open with mine but I only boat in the Colorado river. I made motorplates out of 3/8" aluminum and tapped it directly for 1/2" NPT for my water lines. I'm very anxious to see how your setup performs. Can't wait to see one of these in a gullwing
I'm also very anxious to see how it runs.


You're running an iron block 5.3, right?
 

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Love it!!! Details on the closed cooling please... looks like a mix of some auto and some marine parts. what size heat exchanger, etc?
 

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Discussion Starter #7 (Edited)
Love it!!! Details on the closed cooling please... looks like a mix of some auto and some marine parts. what size heat exchanger, etc?
Thanks a bunch!


Closed cooling was a breeze. When I was working in Corpus Christi, TX I called a guy who had two used heat exchangers for sale. I bought both for $75, and this was the better one.

It's supposedly from a 5.7 Mercruiser; but I've had several people who run HE's on big blocks tell me it's at least as big was what is used on a 7.4, if not bigger. SO...I can't tell you what it's from, but I can get you measurements tonight. EDIT: It's 16.5"x3.25"

Anyway, it's plumbed just like a radiator would be, and I'm using the stock LS1 water pump. It's spaced out 1/4" because of the motor plate; so I just had the stock tensioner milled down 1/4" so all the pulleys line up correctly.

From the pump, I have a water pressure relief kit (no sense in blowing the HE apart with 100 psi water) and runs a 5.8" hose in and 5/8" hose out.

I have a T in the line before the water pressure relief kit, and that is what feeds the water injected headers (with full pressure from the pump).

The engine is 100% auto...
 

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Going to be fun watching this thread. Good luck. I hope it all works out.
 

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Discussion Starter #10
Tested it on a little pond tonight. So far good news...no leaks, except the headers pressure T comes on a little early. I have 1 washer in it to shim it...but I guess I need more.

I do need you guys advice, though. With a 330 hp BBC the pump wouldn't spin over 5000 rpm. But, with this motor I hit the 5900 rpm rev limit pretty quick. This was just on a trailer - will this "load" more when it's actually pushing the boat?
 

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Tested it on a little pond tonight. So far good news...no leaks, except the headers pressure T comes on a little early. I have 1 washer in it to shim it...but I guess I need more.

I do need you guys advice, though. With a 330 hp BBC the pump wouldn't spin over 5000 rpm. But, with this motor I hit the 5900 rpm rev limit pretty quick. This was just on a trailer - will this "load" more when it's actually pushing the boat?

Yes:)hand
 

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Discussion Starter #15
Finally did some testing on the water.

Right now I'm turning what I truly believe to be a B impeller (a 330-350 hp BBC turned this at exactly 5000 rpm) I am currently making 500 hp at 5700 rpm. This is with a very "safe" timing curve and very little carb tuning...so there's honestly a good chance it has quite a bit more in it.


I'm only getting 60-65 out of the boat right now (that was with 4 people and a cooler)...I guess I must have some setup issues? I have a ride plate, but I have NO idea how to set that "correctly".
 

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thats pretty good with 4 people and a cooler.

My boat has a AA and only hits 56 or 57 at 4500 with two people and the back seats installed. Our BBC is turning a calculated 425hp I think it was.

Setting your ride plates correctly should definitely help but you should try getting the numbers with just you in it
 

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Discussion Starter #17
thats pretty good with 4 people and a cooler.

My boat has a AA and only hits 56 or 57 at 4500 with two people and the back seats installed. Our BBC is turning a calculated 425hp I think it was.

Setting your ride plates correctly should definitely help but you should try getting the numbers with just you in it

I'll be honest, I don't know how to set it correctly. But...I'm going to try to get pics today or tomorrow of the loader, shoe, ride plate, and nozzle to see what you experts think.
 
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