If you build a lq9 opt for the stoker (408) if your into refreshoning the engine or building for power. These engines can hold lots of boost safely only if you change your piston ring gap for appropriate boost levels. (On a stock 6.0). But if planning to rebuild go with eagle rotating assemblies as the Callie's compstars series is exspensive. Check Texas-speed.com. For pricing. I assemble my own engines aside from machining work. Price will be between 5-10k for rebuilding with eagle components. Just re-read your original post sorry- I would guess that EFI MSD Set up is somewhere around the 2-2.5k range.

the most popular supercharged 800hp is a 502 or 509 BBC, you can cruise out of boost due to the higher TQ/HP at low rpm's. the LSA 6.2 drinks fuel since it is in boost all of the time. If you built a larger cube LS you start looking at an iron block to reduce crank flex...you end up with more weight over alum and similar cost to BBC with a little less low end power out of boost...in my opinion the LS kind of loses its sizzle. more than 7-800 then you need more cid anyway...BBC.

Great engine but I would prefer the weight savings of Alum if I went ls. A BBC has similar cid but larger bore rather than larger crank...I think the BBC would last longer even if both are iron blocks???

Your engines are insane! I love LS. But I think that the "sweet spot" for power, reliability, and COST in a BOAT compared to BBC seems to be (in my opinion) around 550hp in aluminum.

Your bolck must be re-sleeved and the parts are not exactly off the shelf. are your engines less expensive and more durable than a similar power 598 ci na BBC? Would the BBC have more low RPM power thus faster accelleration? Maybe the weight savings makes up for that???

Ls engines are great due to the higher efficiency gained from the head angle and the light weight especially with an aluminum block. They can also take a longer stroke crank. When researching this engine I wanted a balance between reliability, performance and cost for those two. You can always build something exotic to smoke XYZ.

The engine I think is best is the l96 (ls3 with vvt found in trucks) stroked (4" crank) to 416ci.

Here is why: 1) bore. a stock iron block can be safely bored to a little above 4" and have shorter sleeves that fight a larger crank. The better heads (ls7, ls3) make more power unshrouding the valves with a 4.065 bore. So you either resleeve a block or go with an ls3 lighter alum stock block.

2) stroke. since I would go for the stock ALUMINUM block that allows me to use lager valves and better heads and is lighter without resleeving.... I would not want to go past 4" crank for durability and off the shelf lower cost rotating assembly.

An LS7 runs a slightly larger crank but there is not much to be had in power with 11 more cid but the crank is a little weaker and the rotating assembly more expensive.

If you look at the power band of the LS7 it lacks TQ and low end power compared to a BBC....this is why you may want to take advantage of the VVT which is another tech strength of this engine.

Another way to go is just to get an ls7 crate engine and add VVT cam swap but I would rather build and engine that had incolnel and stainless valves. The CNC heads, dry sump oiling, and extra 11 ci are not that big of a deal.

The lower cid supercharged lsa will be running in boost all the time and the life of that engine will be much shorter than what I have described above.

By the way no one has mentioned that a stock bravo 1 (non XR) would live behind this engine due to the power curve compared to a 502/509 bbc

All these post have shown some really strong pro's and cons to both! Power vs. weight, torque vs. hp ratios and such! But it the end (and I'm a firm believer in LS power) but from a boat standpoint a big block just sounds nasty! And twin big blocks sing a beautiful tune!

I love the LS and want my next boat to have LS power but since VALUE is very important to me I have come to find that there are combinations that work better than others in each application. Since I am interested in light weight 26-30 ft cats I like twin 500hp alum 416ci vvt ls engines with bravo 1's. stock block and heads and stock drives. That will live and not break the bank.

any more than 500hp and you NEED xr's or better. The LS starts getting more exotic and expensive...need boost, sleeved blocks etc. At that point if I were to spend that much money I would be looking at ilmor v10 (many similarities to N/A LS with two more cylinders)...or save some $$$ and just go BBC. 800hp is pretty cost effective with a factory 502 gm short block, dart pro 1 marine heads, whipple 3.3, and CMI e tops....

There is a sweet spot for each application

http://www.youtube.com/watch?v=ibYk_cHpwPA
http://www.youtube.com/watch?v=qREEW8qCnTQ
LS7 WITH WEISSMAN DRIVES. 40 FOOT EXTREME. INLINE DRIVE SYSTEM

I like LS 416 CID for 550 HP too. Click on the dyno graph at this link to see what that looks like when you add a blower. I know its not a marine engine, just using it to put some HP data on the table.

http://www.edelbrock.com/automotive_...rcharged.shtml

LPG offers a 416 SC engine that they rate at 675. Both of these engines may give up some low end torque compared to the BBC, but they can compensate with less weight and fuel.

is that for real? 104mph is the world record for twin v bottom Small Block's?

That seems pretty low?

MP