Originally Posted by missy

700hp, weighing only 560lbs, closed cooled, supercharged, reliable, gm based, for less than $17,000 , that is a hard to beat package

Originally Posted by JIMKID Motorsports

have had them for two years 70 hrs luv em 750 hp na efi

Originally Posted by TxHawk

I would say that the LS engines are just not worth switching to for Merc since what they have has worked. If they were not working on something else, I think you would have already seen a Merc/GM LS Marine engine.

Look at the long block they engineered for the 1350. You can't tell me that after creating that monster that they are going to look at moving to LS engines.

I know from somone involved in Merc "black" engines, that the BBC pushrod engines are going away. If they weren't, it wouldn't be so hard to find new 7.4/8.2 blocks. Even Volvo is looking at options for 8.2 replacements with large contract builders.

Stay tuned...

Originally Posted by Raylar

As the one marine engine company who brought a complete 550HP LS based engine to the market in 2007 and did quite a bit of expensive development and research I can say that these LS marine engine threads always seem to get a little streched and hyped sometimes.
For a little example the air boat link, the company seems like an expeirenced air boat engine builder, but where in the world do they come up with a 376 cubic inch pump gas LS engine that will make 550HP normally aspirated at 5800 rpms! GM's supercharged LSA engine barely gets there an it takes 6500 rpms for that. Its really easy to make claims, its another thing to back them up with independant dyno tests!
The LS engine platform is an excellent engine. With enough $ and expert builds larger cubic inch versions can get to good high torque and horsepower numbers with proper endurance engine builds to be called good long life performance marine offshore engines. They can certainly do the job in certain boat applications such as JIMKID'S LS marine engines do in his Skater. Lets be real here and have him let you know what those 750HP @6800 rpm LS's of his will cost you complete bobtail built and configured exactly as his are done.

Next, please keep in mind that in small jet boats and such these engines can be excellent powerplants as the power and torque available from them in 376 - 406 cubic inch versions to give great results in these smaller lighter boats.
If they are used in 24-27 ft single engine offshore type hulls or 30-35 foot twin engine offshore type hulls they will need to be freshwater cooled and need to produce over 500lb/ft. of torque at 4000-4500 rpms and provide similar 500HP power at 5600-6200 rpms to be considered enough power to push these hulls at BBC comparable acceleration, speeds and cruise speeds. Yes, I know the supercharged versions can do this horsepower and torque numbers at cruise rpms (4000-4200 rpms), but only in boost and you can't expect these supercharged engines to have any good life if they have to cruise for hours in BOOST!

These LS marine engines will still have to do this with comparable costs to the currently available BBC engines that do this reliably and regularly on a reasonable cost basis. There are two reasons this is slow to happen so far in this industry. One, the performance boat market is slower than cold snot for the last three years and two, not many engine companies have created LS engines of this size, reasonable cost basis and type to fill the almost non-existant offshore engine need. Hope this changes in the near future for all of us.

Best Regards,
Ray @ Raylar

Originally Posted by C_Spray

LS engines HAVE replaced big blocks for every production marine power manufacturer except Mercury. Volvo Penta's 430 hp version is now on the market. Volvo Penta 430 hp LS

"V8-430 weighs around 100 kilos less than any other engine in the corresponding classes on the market, resulting in very competitive weight/effect ratios. At the same time, the new engines are heavy-duty, fuel and oil-efficient."

More details on 430/6.0 versus 8.2 Mag

Custom performance builders are another matter, but from the mainstream market point of view, BBC's are dinosaurs.

Originally Posted by HaxbySpeed

Nice work guys! The LS's are coming... We just put some VVT 6.0's in the 29 Blackfin in the pic, just waiting for props 'cause the 400hp 6.0's have a bit more punch then the 330hp 454's they replaced. The X80 behind it is waiting on a pair of LS3's, I just sold another pair of LS3's to a customer in Michigan who's putting them in 1955 Chris Craft Corvette. This other old woody is getting 6.0's and there's more waiting.. I replaced a 496 with an LSA last fall and there is no comparison.