I want a new motor!!!

[D-Volk]

Guys, I know this is a pretty broad question, but I'm in market for a new motor. I currently have a Felber 383, one of the last he produced and I've been running it for 6 years. I've had small issues with it over the years, so it's time to get a new one. What do you think of the Water Thunder 600 hp motors, carb or fuel injected and GTO 427 or 383. Or is there anyone else out there that I'm not aware of who makes a powerful, reliable motor? I'd like some opinions on the motors your running with success stories and struggles. Also, how easy is it to go from a small block to and LS; how different are the front motor mounts. I have a Utah style airboat, so I know our engine stands are different from the Florida style.
Any friendly advice would be greatly appreciated.
Thanks, DV

[GatorgladesJH]

So you want to do an LS swap..

Motor mounts are not an issue with the number of "swap mounts" out on the market today. However there are a few things to consider when measuring the pros and cons of going to LS.

1. If you are currently running a reduction unit/gearbox on your SBC and you want to reuse that same unit you will have to purchase a new flex plate and an adapter as the cranks are different lengths. $350.

2. Fuel systems - EFI fuel systems can be elaborate and expensive. If you are going to run a high hp Waterthunder motor like Dave builds, you are most likely going to have to run an in tank fuel pump to avoid vapor lock. This will require cutting into your existing tank or sometimes it more cost effective to buy a new one. Will you run a return or returnless fuel setup? That is yet another modification.

3. If you jump up a significant amount in hp you are most likely going to be shopping around for more prop to efficiently utilize all of your motor's capabilities.

4. Engine size. Yes LS engines are more compact than the 383 you are currently running, but if your rear seats are too close to the top of the front of the motor you are going to have an issue trying to find a place to run an EFI intake tube and cone. Some people may tell you to throw a little cone on the front of the throttle body and you will be fine... Now where are you going to put your air intake sensor if your system requires it?

5. Is the boat kept inside out of the elements, or is it outside with a blue FEMA tarp over the motor? Something to consider, because I know I would hate to see my $15k EFI LS engine and all of its pricey electronics sitting out in the wind, rain, sleet and snow.

I am in no way bashing the LS motors, I have one myself, but those were a few issues I ran into when doing my SBC to LS swap. Half way through the build I started adding things up and thought to myself, "wow for five grand I could have had a badass, bulletproof, forged 500 hp 383 with top of the line aluminum heads"... not to mention I could have reused all of the perfectly fine parts off my old motor (fuel pump, intake/exhaust manifolds, carb, valve covers, breathers, water pump, etc.) that I sold for pennies on the dollar.

I think I have pretty much covered every thought that will go through your mind once you pulled the trigger on your next build, if none of that concerns you too much then you have nothing to worry about.

If I could make a final suggestion.. Do not try to put an LS motor together. Buy it straight from Dave at Waterthunder. You may think his prices seem high at first but once you start adding things up you are going to be amazed at how he builds his high horsepower, reliable motors for the prices he has listed.

[Thunder200]

Im pretty sure Dave will tell you himself the 418 is the motor to go with. I personally seen the 418s being the most dependable and all th hp you will ever need. JMO

[Tony480]

So you want to do an LS swap..

Motor mounts are not an issue with the number of "swap mounts" out on the market today. However there are a few things to consider when measuring the pros and cons of going to LS.

1. If you are currently running a reduction unit/gearbox on your SBC and you want to reuse that same unit you will have to purchase a new flex plate and an adapter as the cranks are different lengths. $350.

2. Fuel systems - EFI fuel systems can be elaborate and expensive. If you are going to run a high hp Waterthunder motor like Dave builds, you are most likely going to have to run an in tank fuel pump to avoid vapor lock. This will require cutting into your existing tank or sometimes it more cost effective to buy a new one. Will you run a return or returnless fuel setup? That is yet another modification.

3. If you jump up a significant amount in hp you are most likely going to be shopping around for more prop to efficiently utilize all of your motor's capabilities.

4. Engine size. Yes LS engines are more compact than the 383 you are currently running, but if your rear seats are too close to the top of the front of the motor you are going to have an issue trying to find a place to run an EFI intake tube and cone. Some people may tell you to throw a little cone on the front of the throttle body and you will be fine... Now where are you going to put your air intake sensor if your system requires it?

5. Is the boat kept inside out of the elements, or is it outside with a blue FEMA tarp over the motor? Something to consider, because I know I would hate to see my $15k EFI LS engine and all of its pricey electronics sitting out in the wind, rain, sleet and snow.

I am in no way bashing the LS motors, I have one myself, but those were a few issues I ran into when doing my SBC to LS swap. Half way through the build I started adding things up and thought to myself, "wow for five grand I could have had a badass, bulletproof, forged 500 hp 383 with top of the line aluminum heads"... not to mention I could have reused all of the perfectly fine parts off my old motor (fuel pump, intake/exhaust manifolds, carb, valve covers, breathers, water pump, etc.) that I sold for pennies on the dollar.

I think I have pretty much covered every thought that will go through your mind once you pulled the trigger on your next build, if none of that concerns you too much then you have nothing to worry about.

If I could make a final suggestion.. Do not try to put an LS motor together. Buy it straight from Dave at Waterthunder. You may think his prices seem high at first but once you start adding things up you are going to be amazed at how he builds his high horsepower, reliable motors for the prices he has listed.

I've never seen one of Dave's motots with an in tank pump. They all run an external walbro pump

[462kwells]

I have one of Waterthunders 600hp with a carb to keep it simple [no computer] totally satisfied with it, Dave knows his stuff and does not mind taking the time to share his knowledge with anyone just give him a call he will explain anything you need to know

[Tony480]

You can but 2 LS new aluminum blocks for the price of one old school aluminum block and still have money left over

[Bruce]

anything GM performance parts is the way to fly their crate motors have true hp numbers not something someone guesses based on buyin a bunch of parts out of a book and slappin em on a motor, been runnin a crate ls3 for 1500 hours and the only issue ive had is out of the aeromotive pump (which has nothin to do with gm) but that was at 1300 hours so i think the average airboater would be good to go for the rest of their life.

[ls1airboat]

im running a factory LS with all factory gm computer ,harness and efi..inline walboro pump..the boat is working great.

[DynaMarine]

Dave builds a great motor, lots of folks running GM crate motors...Panther sells a bunch I believe. Can't count Keith out (muffled500hp) with his motors. I think he's got the 418, 427 and 454ci LS motors.

We've been very happy with Turn Key Engine Supply's LS motors out of Cali. Wide range of engines to choose from (400hp iron block to 900+ super/turbocharged bad boys. Come with dyno sheet, warranty card and even headers if you want them.

Like Tony mentioned, all the LS motors I've seen run external pumps. Some use a low pressure and high pressure pump setup (Levitator & some MAST) and others use a single high pressure pump mounted at lowest point possible next to the tank.

All great options to source a motor and I think you'll be happy with any one you choose.

[Blackcoffee]

MAS that builds for GTO or Keith as mentioned really does a great job, he is a builder up north that also does all kinds of race and custom motors. He probably has a better choice of engines for you, even with the 383 build.
Why not just change out the motor so you don't have to change the gear box or prop.

[Gobigred1]

Not really even a question. If you want the best call Dave at Water Thunder some of the others may be a tad cheaper but remember you get what ya pay for my friend!!!!!

[Blackcoffee]

Not really even a question. If you want the best call Dave at Water Thunder some of the others may be a tad cheaper but remember you get what ya pay for my friend!!!!!

Have you even looked at Mast or Mas to make make that statement? You might be surprised when you start to compare build parts on those motors to say they are inferior.

[Gobigred1]

Sure have and there is no comparison! Sorry but been around them all and seen it proven time and time again!

[GatorgladesJH]

I've never seen one of Dave's motots with an in tank pump. They all run an external walbro pump[/quote]

You are right. It was not a WT motor I was referring too. My apologies.

[Rich Andrews]

sounds like U should have listened to me

Big Money

[Clint Hall]

Central Florida machine and speed 1 (407) 877-2800 talk to Robert. He'll build you an LS. But my personal preference would be one of his 434's and have big power


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[SWAMPHUNTER45]

Keep it simple, if the 383 has been reliable and fits your needs then why spend a fortune?

If it doesn't fit your needs, the LS3 family brings a lot of gain but HP per $ is quite a bit more with the needed upgrades that were outlined.

[DynaMarine]

Maybe look at a stout 383 and use the Holley Terminator or HP fuel injection on it. Might be a happy medium and get you most of what you want???

[frank w.]

call dave i have carbureted waterthunder and its definitely the way to go .

[Aeon]

As shane from dyna-marine said http://www.turnkeyenginesupply.com/ They are turning out a lot of airboat motors so they are not new to the market.

They built my motor and i could not be more happy with it. i swapped from a BBC to a LS3 and yeah it was a bit of work but worth it. mine gets almost 100% of its use during duck season. So wild temp swings and nasty weather are the norm for us.

as you can see in my video if i can put a LS3 in this old hull any boat can take one. Now if only Shane would send me a dyna marine hull to put my motor on so i can get rid of my ummm vintage hull

[flying fish]

[quote="Aeon"]As shane from dyna-marine said http://www.turnkeyenginesupply.com/ They are turning out a lot of airboat motors so they are not new to the market.

They built my motor and i could not be more happy with it.

ataboy Aeon
Getting it done. enjoyed the video-

[flying fish]

Central Florida machine and speed 1 (407) 877-2800 talk to Robert. He'll build you an LS. But my personal preference would be one of his 434's and have big power


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The 434 if talking 23 degreee motors might not get near the fuel economy compared to a 418 LS ??
My experience anyways-

[Gobigred1]

Central Florida machine and speed 1 (407) 877-2800 talk to Robert. He'll build you an LS. But my personal preference would be one of his 434's and have big power


Sent from my iPhone using Tapatalk

The 434 if talking 23 degreee motors might not get near the fuel economy compared to a 418 LS ??
My experience anyways-

He also says he catches fish too but I aint ever seen it lmao

[DynaMarine]

He also says he catches fish too but I aint ever seen it lmao

Now that you mention it Greg, I have yet to see any fish in his boat....LOL

[Rich Andrews]

Or, if you have not done so already, have the proper carb setup done..it too can do wonders and make more hp than you thought you had. Call Ed Mack in ft laud 954 881 5249