professor_speed

Those area under the curve dyno charts only tell one part of the story. The LS will happily and reliably turn 1000-1500 more rpm. That means you can set it up with more gear reduction in the drive and take advantage of torque multiplication. ie: LS at 6250rpm spinning a 1.65 drive vs BBC at approx 5650 spinning a 1.50 both turn the prop the same. I bet the torque at the prop is very similar once you take into account the additional rpm range, coupled with more gear reduction.

thirdchildhood

iTrader: (6)

Pushrod engines and not enough displacement.

DiamondPerformance

iTrader: (2)

Surprised we don't see more Ilmor MV8 570. 6100 rpm, 564ft/lb @4400rpm

bck

It's a whole recipe that has been more or less worked out with big blocks and I guess it also depends on the boat. I'm thinking a bit more rpm than 6250 to get a solid 600hp. A quick search comes back with a super Chevy build using lots of aftermarket parts making 605 @ 6800. Even if an LS is happy at those rpms what cam specs would be required and would it work with wet exhaust? Then someone's got to switch gears or drives for the correct ratio. How happy is a bravo going to be behind a top gun at well over 6k? Look at the power available at lower rpms how well is the boat getting on plane? How about cruising speed? Plus don't forget the 454 has almost been religated to small block status. For big blocks 502 is the norm and 540s aren't far behind, so the LS is competing with some pretty big cubes.

professor_speed

With a different drive ratio all the shafts in the drive are spinning the same speed they would with a BBC and seeing similar torque I doubt it would be any harder in the drive. Illmore 570 makes the power from 5500 to 6100, 6250 to make 30 more hp with a little more cam and head is not unreasonable. My Z06 makes 700hp by 7000 grated that cam would not be wet exhaust friendly its also 428cid. The point is that the rpm and gear ratio cancel out the lower torque of the smaller engine. Of course there are practical limits. But that's not where the LS shines. Once you get to far away from the GM stock parts dollar for dollar the biggest engine wins. LS makes sense up to around 500-550 NA or maybe 700 with an LSA blower, after that I'm not sure the pros out weight the cons. But most boaters, even here have have power numbers that the LS can compete with just fine.

bck

Those are pretty much my thoughts although once you throw a blower on the LS the comparison gets a bit skewed. You'd have to put a modern blower on the big block to keep it fair. Like you mentioned, the trick is using the modern engineering to get the power and reliability you want very close stock. The more you stray from stock the less sense it starts to make.

MonkeySea2

Several years ago I drove a 28' bowrider with the new VP LS 6.0 liter. The boat also had thru hull exhaust. I have to say I was impressed with the low end torque. The boat hopped on plane immediately and was very responsive. The LS also sounded healthy albite different than a big block. The weight savings over the Merc 8.2 is pretty significant. All in all, a nice package