Well, I also pulled the BBC out of my boat on a farm scale and it weighed in a little over 1180 lbs fully dressed. I then dropped my 408ci LS back into the same boat, on the same scale, and it weighed in at 540 lbs fully dressed. I then changed to an iron block, which added 96 lbs to the engine Bringing it in at roughly 640 lbs fully dressed. That's a weight savings of roughly 540 lbs over the big block. Anybody that tries to say that there isn't a significant weight savings going LS is very misinformed.

That is huge, how much better did the boat perform and ride? Where do you boat?

I was actually surprised at how much better the boat handled, especially in rougher waters. With the aluminum block, the boat was a little out of balance, but the extra 96 lbs of the iron block made it just right. I boat at Lake Cumberland in Kentucky. I know that doesn't get as rough as most places, but on a busy weekend in front of State Dock/Jamestown it turns into a washing machine that can beat you up pretty bad. With the LS I can set it at 45-50mph and it just bounces easily from wave to wave. It stays up on top of the waves with the light weight motor, where it would want to go down and plow through them with the BBC. As far as performance goes, I have seen a best of 77mph GPS, that was with not a lot in the boat and not much fuel. In everyday trim it will run 74-75mph GPS with a 24p Bravo. I still need to do some playing with props as I'm seeing those speeds at 5500-5700 rpms. I want to get it up to 6000-6100 where the engine makes peak power. Then engine made 577hp 530ftlbs and is in a 253 Checkmate Convincor. For what is a non-radical N/A small block in that size boat, I'm really happy. And even though it's carb'd, it sips fuel, and the sound it makes is amazing!!!!!

I have boated on Cumberland a few times, used to live in Indianapolis. The BBC you had, what was it and what did you run? I assume something like a 454 mag or maybe 502 Mag?

Do you have the dyno numbers on the LS and any reversion issues?

The BBC was just a 7.4L 310 hp carb motor. The boat was pretty uneventful with that engine. I saw 60-61mph with it on occasion, but mostly ran in the upper 50's with all of our stuff in it and a full tank. I do have the dyno sheets on the LS, but not with me at work. I know it made 577hp at 6100 rpms and 530-540 ftlbs. I can't remember the exact torque number and what rpm it made peak. What I do remember is that it started making 500 ftlbs at 3200 rpm and didn't stop making 500 ftlbs until 5900 or so. That's what impressed me the most about it being a small motor. I think having the extra cubic inches helped that (408ci). But really, its a mild motor. Stock Gen4 6.0 iron block, Callies crank, Callies Compstar rods and Wiseco -8cc pistons. With the CNC ported 317 heads it's right at 10.2:1 Compression. I run it on 93 octane. Victor Jr. intake, AED Holley hp750 carb and Daytona Ignition Smart Spark LS controlling it. The cam is a custom grind and is 243/250, .620/.613, 112LSA and it reverted like a MOFO!!! I had to make the exhaust totally dry. Even dry to the tip sucked a ton of water in. I have some pretty cool slo-mo video that shows it.

Not bad Corey, the 93 octane would make it unusable here. To hard to find on the water, and a lot of times we do more then 100 miles round trip or like on a Keys trip they never come out of the water for days.

That has been the biggest issue as I look at different motors etc, they have to be able to run on 90. 90 Non ethanol is what most marinas have down here.

Like mggdoors said, this could easily be run on 89 octane if you wanted. My timing curve is really not that super aggressive. I think I idle at 7-10 degrees and only advance up to 27 degrees total at full throttle. Good thing is I have tons of access to 93 Octane both on and off the water. State Dock Marina even has 110 Octane available on the docks. I have a 75 gallon tank and I have gone 120+ miles on it and it still has over 1/4 tank left. I would really like to see e85 come available on the water, I'll run that when I add boost this next year.