Oh no....what have I done......

[yeller]

Yes, this even caught me off guard.
I've always thought about an all aluminum small block, even before the LS motors. Too expensive years ago and only a pipe dream. Since the LS3 came out I started to give it more thought and with there being more and more proven marine LS3's, I was talking with a friend a few days ago who represents several car dealerships for selling their parts and........one thing lead to another......

I like the though of taking a couple hundred pounds off the back and will really enjoy the increased engine room.

Pat, anything over 550hp is fine with me. 600hp is easily done when supercharging these motors, and fairly reliable, even with stock internals. I plan to change the cam, install a rocker arm upgrade, increase the oil pan size, and will probably have to change the balancer in order to accept the SC pulley. Probably be other items that'll have to get done once I get started.
I'll be taking out a procharged 502, which I just got running in the boat this year, after 4yrs of being down. I'll be taking a massive $$ hit in selling it, but that's boating.

[Carl C]

Damn, I didn't see this coming. Uncharted waters. This will be fun to follow. How hard is it to swap a BBC for a LS? Will you have to swap the cams right away? Exhaust will be expensive.

[gcarter]

Exhaust will be expensive.

Maybe, maybe not. There're more available every day.

[gcarter]

I'm still waiting for someone local to install a LSX 454.
A NA setup w/a bit more grunt would be fun.

[Ghost]

I'm still waiting for someone local to install a LSX 454.
A NA setup w/a bit more grunt would be fun.

Was looking at its specs earlier today.

[yeller]

Damn, I didn't see this coming. Uncharted waters. This will be fun to follow. How hard is it to swap a BBC for a LS? Will you have to swap the cams right away? Exhaust will be expensive.

I believe the bellhousing is the same, so it shouldn't be too difficult of a swap. Engine mounts are different and I'm guessing I'll have to patch the transom again and cut new holes for the exhaust.
Cam has to be done right away. From what I can find out, the valve overlap is high and will cause reversion.
George is right about exhaust. There is choices. CMI SS headers are probably at the high end at around $4200. Lightnings have a set for about $3500. But on the low end Marine Power makes an aluminum manifold for under $1k or I could buy a pair of their manifolds without risers for $450 and I'm pretty sure I could make the risers off my 496 exhaust fit. Depends what I want to spend. Lightnings would be my first choice, but I may go with the MarinePower to start with for $450 if cash ends up getting tight.
I have to watch what I spend on this. My wife is NOT happy.

[Carl C]

With a procharger the cheaper exhaust may be fine, as long as it's not too restrictive. You won't need the scavenging effect of headers. They will be lighter too. See how light you can keep the ass end!

[gcarter]

Carl is correct in that headers aren't needed for a supercharged engine.
My vote is to go cheap.

[Pat McPherson]

http://gmpowertrain.com/2013_pdf/FHR...ine_010713.pdf

Hmmm....

[gcarter]

http://gmpowertrain.com/2013_pdf/FHR...ine_010713.pdf

Hmmm....

No point of comparison (other than relative size), and therefore not an argument for either,
but the LSX 454 is 100% forged rotating assembly.

[Pat McPherson]

http://gmpowertrain.com/2013_pdf/M_V...%29_020315.pdf

One of these wouldn't be a bad replacement for my 502...

[RickSE]

This will be interesting to see how it compares to a BBC. These are great motors but one of the things that I've never liked is that you have to rev them up pretty high to get into good power. This is the reason why I have an 8.1L in my truck and not a 6.0L. The BBC is a torque machine from 3,000 RPM on where as the LS motors don't really start kicking until 4,000 RPM. The bigger cube LS's may be different though and certainly a SC will make a difference.

[Ghost]

This will be interesting to see how it compares to a BBC. These are great motors but one of the things that I've never liked is that you have to rev them up pretty high to get into good power. This is the reason why I have an 8.1L in my truck and not a 6.0L. The BBC is a torque machine from 3,000 RPM on where as the LS motors don't really start kicking until 4,000 RPM. The bigger cube LS's may be different though and certainly a SC will make a difference.

Not saying you're wrong about where the torque starts on the 6 liter LS motors, but I'd swear my memory is (from reading Boattest.com test results) that the variable valve timing gave the 6 liter very comparable torque to the 8.2 motors, through the full RPM range. That may be the 430HP 6.0 and the 430 HP 8.2 comparison, where the cam in the high-output 8.2 would weaken it's torque at lower RPM. I suspect the 380HP version of the 8.2 would be different, with more torque down lower. (At SOME place on the curve, the extra cubes have to make more torque, no matter what the valve timing does on the 6.0 to optimize across RPM.)

All that said, I'm 100% with you on the 6.0 RPM going all the way up towards 6000. That's a lot of RPM. If I were choosing for my 24, I"d go with the 8.2 anyway. For an 18 or even a 22, i'm SERIOUSLY interested in what the 6.0 VVT does.

Now, the VVT 454 is another story...THAT would probably tempt me over the 8.2...

[yeller]

The VVT definitely helps. The VVT motor has a better tq/hp curve than the LS3 I have, but not by a bunch.
The LS3 does take some rpm's to get into the hp, but I don't think the tq is too bad. I think it starts pretty early for a small block, with 350lbs at 2000 rpm.
Of course, I plan to bump it up with the SC and about 10lbs of boost. I'm contemplating setting up the blower to run about 15lbs but wasting anything over 10 so the power will come on sooner.

[RickSE]

Yeah most of my observations are from the 8.1L in my truck. It does an amazing job of pulling up a hill with a heavy load at 3,200 RPM vs my friends 6.0L's that need +4K RPM's to do the same.

This should be a cool combo. Is it done yet Glen & can you send an extra motor down for my 65 Olds wagon?