LS repower!! Need help

Automotive powered airboat discussion.
2WHEELER
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LS repower!! Need help

Postby 2WHEELER » Sun Feb 26, 2017 11:23 am

I have a cadillac 500 gearbox boat I am fed up with it!! What is the best way to get my hands on a aluminum 6.0l ls? I want to keep the budget down as best as I can! I would like to keep it injected. What do I need to look for when buying a ls that will be costly if it is not included in the original purchase? Thanks in advance!!

CarMotorBarge
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Re: LS repower!! Need help

Postby CarMotorBarge » Sun Feb 26, 2017 3:18 pm

For an aluminum 6.0, you need the LS2 or L76 engines. These aren't that easy to find for a low price. A cheaper option is to find an L33 5.3 engine and put a little bigger cam in it. Another option is to get a 6.0 cast iron motor. They way about 120 lbs more than aluminum.

When you buy an engine, try to get the factory ECM. You can purchase a package like HPTuners to tune it. Personally I have been using the Holley HP EFI because it is a standalone EFI system that is easier to tune, but it costs about $1,800.

You can also put an MSD box, carb, and carb intake on the engine. The MSD box costs about $375 and the carb intake costs $250 to $300.

Also try to get all of the accessories such as the alternator and pullies. All of this adds up in price.
14x7.5 Al David hull with 14 inch transom
419 CI Horsepower Barn LS3 with 2.68 Rotator soft drive swinging 4 blade 83.5" R
GTO Rigging and B&S Tilt Trailer
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2WHEELER
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Re: LS repower!! Need help

Postby 2WHEELER » Sun Feb 26, 2017 3:40 pm

So if I go with a carb and a msd box I don't need the factory harness?

CarMotorBarge
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Re: LS repower!! Need help

Postby CarMotorBarge » Mon Feb 27, 2017 6:35 am

I have never put an MSD box on. I have always used EFI. However, all of the boats I see on the river it doesn't appear to be a factory harness. I am not sure if the harness for the MSD comes with it in the box or you have to buy it separate. You should be able to call MSD and find out for sure. The MSD hooks to the crank sensor, cam sensor, knock sensors, and coil packs. It only controls spark and doesn't control fuel. I was reading online and it looks like the newest MSD also hooks to the water temperature sensor. Also where are you located?
14x7.5 Al David hull with 14 inch transom
419 CI Horsepower Barn LS3 with 2.68 Rotator soft drive swinging 4 blade 83.5" R
GTO Rigging and B&S Tilt Trailer
Member of Seminole Airboat Club

One Eyed Gator
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Re: LS repower!! Need help

Postby One Eyed Gator » Mon Feb 27, 2017 7:28 am

I have a 5.3 that is carbed with MSD on a 14' Alumitec. Motor is stock had 113K out of wreck Silverado. I have run it with a 2:1 and now a 2.68. Has over 400hrs between 2 different boat. Built a 14' Alumitec deckover (older Round Bottom hull) with a L33 5.3 That motor turns motor prop with a 2.55 box then my motor with a 2.68.
Just finished a 6.0 boat with 2.55. That motor is stock, stock EFI with Holley terminator. Was plug and play, motor started and ran 1st turn of the key. Nice system but expensive. Buddy paid 1500.00 for 04' 6.0 out of a denali with 78K. Complete motor without harness. You can buy a 5.3 for 750.00-1200.00 or the 6.0 for about 750.00 more. LS2 and L76 are the aluminum motor. You can get an idea if you what vehicle the motors come out of go to www.car-parts.com. You have a-lot more option with 6.0.

If you decide to buy the MSD box buy the box and intake separate, the msd box in the edelbrock brock kit with not allow you to do any custom timing curves. Also I was able the use the harness that cam with box without the extension and still mount the box under my back seat. If you do not mount the msd box on the intake you have to block-out the mounting hole that goes through to the runner.

Went from a Cadillac DD to a gearbox to Gearbox and LS, love my Cadillac but would not go back.

Don't live to far from you let me know if I can help.


One Eyed Gator
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Re: LS repower!! Need help

Postby One Eyed Gator » Mon Feb 27, 2017 7:31 am

No you do not need factory harness with MSD set-up.

2WHEELER
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Re: LS repower!! Need help

Postby 2WHEELER » Mon Feb 27, 2017 7:43 am

One Eyed Gator I think you got some cadillac parts from me years back! I don't really know what I need I found a iron 6.0 cheap with low miles but it is a 2014 vct does that matter? pm me your number I would like to talk with you

One Eyed Gator
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Re: LS repower!! Need help

Postby One Eyed Gator » Mon Feb 27, 2017 8:18 am

Yep that was me.

Pm Sent

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scottyroll
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Re: LS repower!! Need help

Postby scottyroll » Mon Feb 27, 2017 11:24 am

2WHEELER wrote:...I found a iron 6.0 cheap with low miles but it is a 2014 vct does that matter?


From my research and personal experience, you do not want an engine that turns some of the cylinders off via VVT.

I had a 5.3 in my GMC Envoy XL and it blew the top end and then the bottom end after the top was fixed.

Perhaps it can be eliminated thru programming. Not positive.
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CarMotorBarge
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Re: LS repower!! Need help

Postby CarMotorBarge » Mon Feb 27, 2017 6:42 pm

The VVT doesn't deactivate the cylinders. The AFM deactivates the cylinders. The VVT advances and retards the cam timing. I definitely agree that you don't want AFM on an airboat. However, I am not sure that the engine 2wheeler found has AFM. I think it is probably an L96 engine and if so it doesn't have AFM.

For the VVT if you get an ECM that can operate the VVT, it might make sense to keep it depending on what you do to the engine. There are advantages to VVT. If the ECM you get doesn't work with VVT, I would get a VVT delete kit.
14x7.5 Al David hull with 14 inch transom
419 CI Horsepower Barn LS3 with 2.68 Rotator soft drive swinging 4 blade 83.5" R
GTO Rigging and B&S Tilt Trailer
Member of Seminole Airboat Club

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scottyroll
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Re: LS repower!! Need help

Postby scottyroll » Tue Feb 28, 2017 7:19 am

CarMotorBarge, thank you for clarifying for the OP. I mixed up my acronyms lol.
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FLAwless

14ft Laser/6.0 LQ4/2.37 Rotator/3 Blade "K"


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