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Discussion Starter #1
New guy, first post!!

Long story short, I have a garage full of parts from previous projects including a complete running 4.8 out of an 05 express van. I always wanted a jet boat, and came across this engineless 79 Taylor SS.



I went and got it a while back, brought it to a friends barn for storage for the winter.

So the plan is the 4.8 and 2 70/65 ebay turbos I have. Cam, head studs, valve springs, and push rods only. 2 air water intercoolers. It will probably make 700-750 hp @ 20 psi @ 6500rpm.

Pretty sure its a berkeley je pump.

I want to run closed cooling. I can get it set up, but where do I find a reasonably priced heat exchanger that will cool this thing? Will a big block chevy heat exchanger do it? What about this one? Marine Heat Exchanger 18 3 4” Long by 3 1 2” Diameter | eBay

I understand this hull shouldn't be pushed for big mph. Can the pump be set up for say a 70mph top speed with brutal acceleration???

Any other input, good or bad?

Thanks.

Ryan
 

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New guy, first post!!

Long story short, I have a garage full of parts from previous projects including a complete running 4.8 out of an 05 express van. I always wanted a jet boat, and came across this engineless 79 Taylor SS.



I went and got it a while back, brought it to a friends barn for storage for the winter.

So the plan is the 4.8 and 2 70/65 ebay turbos I have. Cam, head studs, valve springs, and push rods only. 2 air water intercoolers. It will probably make 700-750 hp @ 20 psi @ 6500rpm.

Pretty sure its a berkeley je pump.

I want to run closed cooling. I can get it set up, but where do I find a reasonably priced heat exchanger that will cool this thing? Will a big block chevy heat exchanger do it? What about this one? Marine Heat Exchanger 18 3 4” Long by 3 1 2” Diameter | eBay

I understand this hull shouldn't be pushed for big mph. Can the pump be set up for say a 70mph top speed with brutal acceleration???

Any other input, good or bad?

Thanks.

Ryan

Hi Ryan,
Sounds like a very doable project. That hull will probably be very scary with that kind of HP.

Im running a rogers that is fairly heavy and generally a "quicker" boat. I have a 5.3 in it with ls6 (243) heads, 10.0:1, and a BTR stage 4 cam with a carb.

My boat runs 71 on motor on gps. I have not even dialed the tune in yet. It does 82 on a 150 shot of giggle juice.

Your boat should accelerate like crazy. But with that kind of power you will pass that 70 mark easily. But not safely.

The pump will need to be built and should have a stainless heavy duty shaft, inducer and stainless impeller.

Im all for LS builds, but imo that will be beyond overkill in that hull.

Is it a 1/4 stringer boat?
 

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Discussion Starter #3
Your boat sounds awesome and thanks for your input. I don't know if it is a 1/4 stringer. I had more pics of the boat including the engine area, but they are lost in cyberspace. And don't know if that pic would help to tell, anyways. It has a (solid) carpeted floor ahead of that. I won't be by the boat anytime soon.

I figured the pump would need some upgrades and prob needs rebuilt anyways. It can't be set up to "limit" top speed? Still learning about jets.
 

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Your boat sounds awesome and thanks for your input. I don't know if it is a 1/4 stringer. I had more pics of the boat including the engine area, but they are lost in cyberspace. And don't know if that pic would help to tell, anyways. It has a (solid) carpeted floor ahead of that. I won't be by the boat anytime soon.

I figured the pump would need some upgrades and prob needs rebuilt anyways. It can't be set up to "limit" top speed? Still learning about jets.

to my knowledge, there is not a way to "limit" top speed. You can put a giant ass impeller in it that your engine cant turn but that just wont be right.

That 4.8 will make a lot of power on the boost, but not a shit ton of torque to turn a big impeller down low.

I spin a BC to 5400 on motor and about 6400 on bottle.
 

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Discussion Starter #5
I understand what you are saying. But wouldnt that load the engine even harder to get the turbos lit, though? Could get the cam specced to help as well?
 

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I understand what you are saying. But wouldnt that load the engine even harder to get the turbos lit, though? Could get the cam specced to help as well?
Thats out of my knowledge realm... i really dont know. The guys on LS1Tech might be able to help.

I'd venture to say it would work, however it would not be efficient. But again, im no expert and really dont kwno
 

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The je pump in the hull is only gna be good for around 80ish before youre hanging so much hardware below keel level it becomes dangerous on shutdown. The 4.8 will be fine against it but youre going alil too big on turbs imo. A 65-65 type deal would spool faster on a turbine ar of less than .81. I think most come around .65 anyways. Thatd spool quick against a a-cut impellor.
 

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Im not trying to be negative about the project i actually think its a great one. Ive just owned a taylor sj which has the same bottom as a ss and mine had a je pump. With 750hp nitrous bbf and hitech shoe and ride plate kit i got it into the mid 80's, but it was dangerous as hell and would ocassionally turn lh on shutdowns. Spooked me so bad one wknd by the next id went out and bought a tx19 lol. Gta bit of experience with turbo ls too. I know of some 200 buck turbs thatd be perfect for his deal.
 

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Im in the same boat as you are. I think its an awesome idea, and im a huge fan of these LS engines in boats. They seem to work very well.

But i just dont think it would be safe to have that kind of power in that hull
 

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Im in the same boat as you are. I think its an awesome idea, and im a huge fan of these LS engines in boats. They seem to work very well.

But i just dont think it would be safe to have that kind of power in that hull
I agree and if he already owns the big turbs he could sell them and buy smaller faster spooling turbs that meet his hp goal better.going to big makes for a slow spooling motor. Better to have 800hp worth of turbs with a 750hp goal than 1200hp worth and shooting for 750.
 

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Discussion Starter #13
Thats out of my knowledge realm... i really dont know. The guys on LS1Tech might be able to help.

I'd venture to say it would work, however it would not be efficient. But again, im no expert and really dont kwno
Thanks. I have been on ls1tech for a while. Hence the reason I have a surplus of parts....lol

The je pump in the hull is only gna be good for around 80ish before youre hanging so much hardware below keel level it becomes dangerous on shutdown. The 4.8 will be fine against it but youre going alil too big on turbs imo. A 65-65 type deal would spool faster on a turbine ar of less than .81. I think most come around .65 anyways. Thatd spool quick against a a-cut impellor.
Thanks for the info on the pump. I ordered these 70/65's with a .68 ar (for a 6.0 in car)



^^^ There you go
Im not trying to be negative about the project i actually think its a great one. Ive just owned a taylor sj which has the same bottom as a ss and mine had a je pump. With 750hp nitrous bbf and hitech shoe and ride plate kit i got it into the mid 80's, but it was dangerous as hell and would ocassionally turn lh on shutdowns. Spooked me so bad one wknd by the next id went out and bought a tx19 lol. Gta bit of experience with turbo ls too. I know of some 200 buck turbs thatd be perfect for his deal.
Yeah, that don't sound fun. I have some experience as well with turbo ls stuff, albeit not it in a tiny boat. Almost done with an ly6 BW S480 in a 94 fleetwood.



Im in the same boat as you are. I think its an awesome idea, and im a huge fan of these LS engines in boats. They seem to work very well.

But i just dont think it would be safe to have that kind of power in that hull
I agree and if he already owns the big turbs he could sell them and buy smaller faster spooling turbs that meet his hp goal better.going to big makes for a slow spooling motor. Better to have 800hp worth of turbs with a 750hp goal than 1200hp worth and shooting for 750.
Yes I already have them.
truth be told, a 5.3 crank, a decent cam, and NA he wouldnt be far from his goal lol
Not opposed to NA. Prob resell easier! But the engine isn't coming apart.
And you would need a 5.3/6.0 crank and rods. The 4.8 has a longer rod to make up for the shorter stroke.:)
 

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Not opposed to NA. Prob resell easier! But the engine isn't coming apart.
And you would need a 5.3/6.0 crank and rods. The 4.8 has a longer rod to make up for the shorter stroke.:)
You are right, i forgot about that little bit when i was looking for 4.8 pistons for my engine. Stuck with the dished ones
 

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Looks like a fun project. There is a boat like yours on our lake that is black with yellow and orange flames. It looks crazy/cool and it hauls ass.

I wouldn't worry about all the details (except your tune) until you run it on the water. You can always limit your speed by not going WOT for too long if it proves to be squirrely lol

Put up some pictures as you go!
 

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Discussion Starter #16
I always take lots of pics.

Maybe I will just get it together with the stock cam and low boost and see what happens. I think the guy said it has a b impeller.

Does anybody have input on a heat exchanger for the closed cooling system? Sized for the 800 hp even if it never gets there?
 

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I always take lots of pics.

Maybe I will just get it together with the stock cam and low boost and see what happens. I think the guy said it has a b impeller.

Does anybody have input on a heat exchanger for the closed cooling system? Sized for the 800 hp even if it never gets there?
It really doesnt need one, the jetpump provides plenty for the motor. I fed my last tt 5.3 with a 8an split at the motor into the lower waterpump ports then each top port had its own 8an outgoing. I took a pressure reading on it and was only seeing 17-20psi build up in the block. Ls is reverse flow but i run em like you would a sbc or bbc as far as cooling them. Keeps from having to use the steam line bs i block those off
 

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It really doesnt need one, the jetpump provides plenty for the motor. I fed my last tt 5.3 with a 8an split at the motor into the lower waterpump ports then each top port had its own 8an outgoing. I took a pressure reading on it and was only seeing 17-20psi build up in the block. Ls is reverse flow but i run em like you would a sbc or bbc as far as cooling them. Keeps from having to use the steam line bs i block those off
Thought LT1 was the only reverse flow? Anyways, I want to run a heat exchanger. Mainly to get the engine up to proper temp for efi.
 

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Oh, and I have some of the olds 403 parts are they worth anything? Exhaust manifolds, bellhousing, starter, and I am sure a couple other things.
 

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curious, how is the keel transition into the intake on that boat? is it a smooth, flat/continuous surface or are there any recess type steps/bumps as it transitions from the hull keel into the pump intake?
 
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