I found a few good articles about people putting an LS1 into Donzi's and Baja's, but what about a 1979 Ski Natique? I have been thinking about this swap for a while- either a big stroker LS1 with a carb or a stock cube twin turbo show boat. We dont use the boat much anymore for skiing or wakeboarding, and were thinking of just doing a really awesome show/go boat. I know ski boats arent built for speed and a 1000 hp LS1 would be a little much. But what kind of drive would work well with these set ups. I think right now I just have a 2 speed Huber transmission..
Any thoughts?

 

Would be a cool swap, but....

Your going to have to pay very close attention to marinizination of systems.

I Googled marinazition and found:

http://www.boatdesign.net/forums/showthread.php?t=650

The big thing is making sure that things are spark and leak proof. Other wise you are sitting on a bowl full of gas fumes waiting for a spark!

Later,

Matt

PS Rember, with the fixed prop angle the harder you push, the wetter you will ride. I would guess your top speed numbers will be a lot lower than you expect even with 1000 hp. YOu might need to look into some trim tabs to try and get the boat to lift its self out of the water a bit more.

 

I can`t really comment too much on a drive setup, since I`m a jet guy. From what I hear direct drive ski boats don`t really make good go fast performance boats. It might be better if you changed from a direct drive to a V drive setup, that would help get the center of gravity further back where you want it for performance plus you could probably cut down the propshaft angle a bit so that more force is used to push the boat forward instead of upward. I don`t know how that would affect the handling though since ski boats are designed to have the CG further forward.

The degree to which you would have to marinize the motor depends on if it is enclosed. If the motor has a full cover over it you will need a flame arrestor, marine starter, and alternator. Last time I looked into it for a marine motor that is open with no engine cover you just needed a marine carb and flame arrestor, you didn`t have to worry about having everything spark proof since the engine is exposed and the chance of vapors building up is almost nonexistant.

 

Those boats are designed to ride low in the water even on plane and create a nice lip for wakeboarding...They're not meant for speed. We have a mastercraft with a 454 in it and it'll still only do about 55-60 mph, but it get there alot faster.

 

I kind of doubt in 1979 Ski Nautique was too concerned with the shape of their wake for wakeboard tricks since wakeboards probably weren't invented for another ~10 years It's been forever since I've skied behind an old Nautique (or any boat for that matter), but if I remember correctly they had a really small and soft wake.

 

Sounds like a lot of work for what you are going to do with the boat. Sell the Ski Antique and put the motor into a Pickelfork if you want something cool! Lightweight engine in a light high-speed boat!

 

Bingo, but you can sack the boat for a bigger wake and have a nice shaped wake riding the wakeboard.

 

Well the whole idea behind this conversion was basically to make a conversation/show piece. Like I said, it wont be used much anymore for skiing and wakeboarding- maybe just a little putting around the lake on occasion.
This boat has been modified for competition (dual speedos, transom and keel fins) for skiing, so the wake is very minimal. Even with the old 351W, she'll do about 50 mph..
Im basically just wondering if anyone makes risers to fit onto an LS1, as well as transmission adapter plates.

 

The More Horsepower you put in them the more the bow wants to plow. Do to the angle of drive ,we had a viper V-10 in one It Was not Fast . but got out of the hole quick.We also had a special prop made just for it. but was neet.

 

Semi-planing hull, mid engine, 6 foot beam, it just doesnt add up to a show and go. I guess it would be cool to say you have an lsx in an old correct craft, but you still have an old correct craft. As far as I know, there arent any manufacturers making water jacketed exhaust. The tranny isnt a big issue...the old bw or velvet drive will be fine; but I would def change the camshaft. most of those trannys in the nautiques were only 1:1. You would get alot of looks if you had that combo- but you would get twice the lookers with an old flat bottom vdrive. To each his own.

 

GM is building 6.0 engines (caddy) for several of the ski boat builders now. So there is your manifolds (they are pretty trick) and trans adapters plus all of the cooling components. Just go to your local ski boat dealer to see one.

 

A few years back Malibu ski boats were using ls1's, so I am sure the parts are readily available. You should look into them if you weren't allready aware of the fact.

 

I work on malibus alot- never seen an ls1. The old mastercraft maristar had lt1s.

 

I'm very interested in this swap myself. I just got a tournament ski boat w/ a bad 351W in it and would love to go LSx route. Well risers are available out there, buy I would have to figure the cooling portion out as I wouldn't wanna just go by all the marine stuff as it would add up $$ quick!! Then that leaves the mounting. Motor mounts would be easy but would need an adapter for the drive mounts. The splines wouldn't be to difficult to figure out though. As far as the intake, would it be better to use a truck intkae considering the RPM usage and for TQ?

Jason

 

This is completely do-able, using pretty much off the shelf parts.

A couple of companies are offering fully marinized 6.0L Gen III's. They're available in a couple of ski-boats as standard or optional motors. Should also be able to get them in other types of boats. I can't remember which engine manufacturer's are running them, but there aren't that many, shouldn't be hard to figure out who's got what.

Manifolds are available, but I bet they aren't cheap. I think one of the marinizers had ones cast from aluminum for light weight (not sure how well they'd last in salt water.....).

The transmission adapter shouldn't be a big deal. The LSx pattern is pretty close to the standard SBC/BBC pattern. Really just need an extra bolt boss (12 o'clock position, since you can't use the 2 o'clock position due to no hole), shouldn't be that big a deal to weld on the extra boss. Most of the velvet drives and such have replaceable bellhousings, so it should just be a matter of swapping the Ford bellhousing for a GM bellhousing.

I'm not sure what you'll need for a flywheel, but I expect there is a stock offering that will do what you want. May need the 4L80E flexplate spacer to get it into the correct position.

You will still need to figure out what to do with the high pressure fuel pump. I don't think I'd want to put it in the tank. I'd suggest a 2 pump system, 1 to draw fuel from the tank, and the 2nd to pressurize it and send it to the engine. Come up with some kind of can to mount the 2nd pump in so that it always has fuel regardless of boat attitude (slosh / pitch / roll / whatever).

Search around in this forum. The LS1 boat idea has been talked about. There is more info in there.


Lastly, you should ask the question of is this worthwhile. One of the other guys suggested a picklefork, which might have more of the oooh-aaaah factor than a 27 year old Correct Craft. Maybe an old Chris Craft or Century (pretty mahogany one) would be more fun.

'JustDreamin'

 

If you are looking for the marine parts to do an LS1 swap let me know i am trying to get rid of the parts from a 2002 Malibu LS1 Ski Boat. I have all the marine parts/ harness/ecu/manifolds/transom mounts/ bell housing/ flywheel/ fuel pump/alternator/starter/etc if you need them.

Scott

 

How much do you want for the bellhousing and flywheel?

 

Oh, and is the alternator a sealed marine grade alternator?