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LS1 DD project boat.

Waterthunder

Waterthunder

Well-known member
I was going to build a 15 or 16 foot twin turbo 1000plus HP LS7 boat. Well after driving two 15 and 16 foot boats in the last week I realize I don't like big airboats The boats run great actually very impressive but I just didn't enjoy driving them at all. I just love a 12 to 13.6 boat to me nothing rides like them. So my twin turbo project is being parted out. After 15 years of hearing it's only a 4 banger or it's only a 220 I figured the least respected and poorest performing airboats are DD car motors, accept of coarse Caddy's. So Why not build a cheap but good performing LS1 DD car motor boat. I already have a motor and hull I just need to rig it and buy a used A/C Warp Drive. Right now every free moment is prepairing for the Sarno Race but I will have the DD LS1 boat done by the end of Jan.
 
Well thunder I can appreciate your sentiments on the big boats. I am sure my new one is running every bit as good as my last one but it just isn't the same.

My new one is only a foot longer and 6" wider but the deck is huge and it has 12" walk boards on the sides. I know it runs just as good for sure now because I went back to some rather challenging holes where I tested my boat before and it passed just fine, actually rather impressively. However the hot rod feeling just isn't there and it may be just a mental block but the sensation of speed and power are missing from the drivers seat.

I think a DD project would be interesting, I don't know how much of a hotrod it will be but it should be interesting to say the least. good luck and keep us posted.
 
Country that is funny we have the same exact sentiment on big boats. I thought long and hard because I want to build a big twin turbo boat. But this week I realized two things one I always seam to ride by myself or one passenger. Two I believe no matter how much power I put on a boat if it's over 14ft it will not handle or perform the way I like an Airboat to perform. Me and Sniper just got off the phone and we were talking about the point when you only add one foot more to an airboat and it changes everything and becomes a pontoon boat. I know how you research everything to death and make logical decisions I'm sure your rig is a nasty combo but even after all that it just don't feel like an airboat anymore at least that's how the big boats feel to me.
 
Thunder, I hate to sound stupid but if your building a ls1 for direct drive you don't want that much horse power do you? Won't you over turn your prop if you push to much hp on a dd unit??
 
You can't make that much power with a DD car motor. That's why everybody builds a motor to make torque hence the Caddy's and 454's. I will try to build a good LS1 for low end torque and horsepower. I believe I can make around the same HP as a O540 or 520 and be somewhere around 40 to 100 pounds lighter. The toughest factor will be over coming the lack of torque and only being able to turning 3,500RPM's. But hey I love a challenge, there are three reasons I'm doing this and one of them involves a bet with a good freind that I must win!
 
Dave, don't over look the fact that most guy's that have bunch of money to spend want a bigger rig. You've open people eyes to power plant that is lighter and stronger than a 540 on a small boat. What about a bigger boat set up. Sometime you have to build something that not to your like, to prove a point of "thinking out side of the box". Which you have done well so far.


Geoff
 
You are so right. However I have absolutely no interest in building motors for big rigs for several reasons. I like to build efficient things that perform. Also I have seen the headaches with those high dollar million dollar rigs. People tend to think because they spend so much money their boat should be able to over come the laws of physics. I also enjoy dealing with the type of airboater I'm presently dealing with the ones like myself who respect and understand their equipment. Every customer has become a friend of mine and enjoys their airboat so why would I change anything. You all can call me a fool but I have no interest in chasing the big money boat customers. And because of this I haven't had to deal with the misery that a close friend who only deals with the high dollar rigs does. I think he may be posting on here shortly about the misery he has gone thru.
 
10'-12' 1000lb rig, 300+ hp....hard to top! Probably doesn't matter what kind of engine as long as its instant reving. If you haven't ridden this kind of boat you won't understand....nothing wrong with bigger heaver boats....just not the same!

Grant
 
Zackly thunder, kinda like when I called you and told you about the sensenitch prop, my feelings on that was it was a turd but the computer said it was a champ, it was all in the perception of things it was too quiet to have power LOL, oh well we run em now.

My big boat is really a good one, I run just as fast on top end as some smaller lighter boats, I run ground and climb hills just like before, however it just don't fell the same way. It jumps on plane quickly, It burns the same fuel amount. But when you are sitting on that triple wide seat looking across 40 acres of front deck something just gets lost in the translation.

good luck on the DD it can be done I am sure.
 
I don't like building LS1's or A SBC for boats over 15ft because performance does't really matter any more. I prefer to build BBC's for boats over 15ft because weight is no longer an issue.
 
I was reading an old issue of HotRod @ the station yesterday in my office and there was an article on the LS7. As soon as I saw the part that said the heads were made to handle 500+HP I thought to myself what kinda boat is Dave gonna have when he builds one of those LS7's. Then I came home saw this thread and it answered one of my many questions. Dave, how is the fuel economy on those LS7's and have you ever built one?? I know this is off topic but I was thinking about a powerplant for my 68 Camaro. Would an LS7 be a good choice??, the car is gutted and weighs about 2600 lbs. I have a Turbo 400 tranny that was in a Super Gas Camaro that was running in the low 9's.
 
THANK YOU FOR DOING THIS BUILD . MY DAD AND I HAVE 13.6 X 8 JIMMY WHITE WITH A DD SBC 400 BUILT FOR LOW END IT DOES PERTY GOOD , IVE BEEN WONDERING ABOUT ABOUT A BIG INCH LS1 DD ,I CANT WAIT TO SEE HOW YOUR BUILD TURNS OUT GOOD LUCK I DONT THINK YOU ARE GONNA NEED IT THOUGH . JUSTIN. P.S. ARE YOU GONNA SROKE IT AND SLEEVE IT TO 427CID? :twisted:
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Thunder, I am running a sbc 350 ,330hp and a franklin belt drive on a 15 ft hull, its a family boat,hunting,froggin etc. It dosen't starve for power and runs the hill pretty good loaded down,and also does real good on fuel,I notice you talk about gear boxes mostly ,my question is would it be better when I wear this 350 out , to go to a LS1 and keep my belt drive and save some money or change over to a gear box?Like I said this is a family boat and im not lookin for a bunch more hp,just lookin to nock some weight off.
 
To be honest I would keep the engine and go with a 2.68 gearbox. Because an iron 350 with a 2.68 gearbox will swing twice the prop as a 500HP LS1 with a 2to1 belt drive. For my DD boat I'm going with a LS1 block with a 1/4 inch stroked crank which will give it a 4.00 stroke. As for the Camaro I love the 67's and 68's I have owned a few. I would build a LS2 block with a 4.00 arm this will give you a 408 they make gangster broad power. I'm not a huge fan of the LS7 they are expensive and there are issues with the titanium rods and I don't like a belt drive sump on a airboat or street car you can convert them but I just prefer the LS1 or LS2 motors and pick the exact parts I like and save money!
 
Thunder, my boat runs pretty damn good for a direct drive.
The hull is VERY heavy....

With your resources for making power, and the light weight of the LS1, you should be able to put one on a hull that doesn't weigh too much and I bet it'll run like stink.

The only thing is it will probably make a lot more sound than your current boat.
 
Hey Thunder,

Great idea building a DD in a lightweight package. If for no other reason, the one thing that the Cadi's will eventually run out of is timing chain covers. Little things like a timing chain cover, brackets etc. can sometimes be a headache. With SB chevy you buy any part almost anywhere. And, with the right setup a DD is just perfect for a lot of folks.

Good luck on that project.
 
hey capt.catfish there is a company that makes stainless timing covers for the caddy.they just aint cheap like aftermarket pulleys but potter makes an alluminum alternator bracket that is inexpensive and looks nice.
 
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