I was reading some old articles about an all aluminum ls based 550hp powerplant, was this project shelved ?

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if you're looking for an LSx motor that produces 550HP, I know a guy in Tennessee who builds them




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Pretty much any cam and heads LS is 550 hp. lol

=Why not just buy a aluminum big block and build it from there.These 550ls motors are small blocks right

A aluminum big block would still weigh less than a regular small block.
https://www.theengineshop.com/produc...num-block.html

I think MAST was advertising one. The Illmor has an iron block which I think defeats part of the appeal of an LS. Would love to a see a really affordable light weight 500hp 6.2L aluminum package.

The problem is the market is too small. Youll have to do the leg work and put your own together. But it shouldn't be that challenging.

https://m.summitracing.com/parts/nal-19301358

great price. How much to marinize is the question.

No substitute for cubic inches. Whatever you do to a small block you can also do to a big block. If you have light boat the small blocks will work nice. My 2 cents

I agree with small cube LS motors. They work great in light cars with 6 speed transmissions but have not proven to work in heavy boats yet. Now add boost to them and ball game changes but in NA aspirated form they lack the displacement needed in marine world. Formula built a 353 with Ilmor LS motors in it and did not perform very well compared to 525s and where rated at 550hp if I remember right.

Agree with what everyone has said. I'm a huge LS guy (I've done 8 car LS swaps and one jet boat) but they just don't have the low end torque to push a heavy V-bottom onto plane. The main problem is most LS engines that make 450+ NA really have to get spun up to make those power numbers. In my mind, a pair of LS-s in a bigger v-bottom would need to be at least 400 cube per side to make sense.. Or simply add boost. With boost, one problem is gone but another comes into play: Keeping the IATs down. Any factory GM blower is going to start turning out some high IATs at 100% throttle for a long run.

That said, cost aside, I think the ticket would be a quad-engine 6.2 boat with two engines tied together on each side. Essentially 12.4 liters & 800hp per side and a velvety smooth idle. Reliability like a 496HO. Cost could be reduced significantly with junkyard aluminum 5.3s. The issue there is finding something with enough room to fit without having the throttle body of the front engines under the rear seat! Maybe a staggered boat turned back into a sideXside config but who would want to do that??

Brandon

Correct, boat is on Lake Erie Sandusky area, now its up for sale. A few years ago we had an 05 353 525/ITS boat and we ran a little faster than that Ilmor 353 small block boat in a Poker Run. Very nice looking engine but performance was not impressive enough to say out with the BBC and embrace this new LS SBC technology for me. I can see where the LS would work in a smaller, lighter boat.