[1Gary]

Honestly if in knowledge I am weak in it is the LSx engines.I am trying to research that as fast as I can to shore up that.At 65 yrs old I have spent my entire life in first gen Chevy's.

But for now the primary question I have is how does the LSx engines compare to like a 383 in TQ and power curves??. With the 383's you can build tons of TQ right off idle.Does the LSx engines tend to come into their power curve later in the RPM range??. From what I have read the LSx's you can build alot of HP and get great gas mileage too.Kind of a cake and eat it too thing.The other thing I have read is the 6.0 is a gas hog.

I trust the input from here. It does seem to me there are a number of very knowledgeable engine builders.

Please and thank you in advance.

[ap72]

Originally Posted by 1Gary

Honestly if in knowledge I am weak in it is the LSx engines.I am trying to research that as fast as I can to shore up that.At 65 yrs old I have spent my entire life in first gen Chevy's.

But for now the primary question I have is how does the LSx engines compare to like a 383 in TQ and power curves??. With the 383's you can build tons of TQ right off idle.Does the LSx engines tend to come into their power curve later in the RPM range??. From what I have read the LSx's you can build alot of HP and get great gas mileage too.Kind of a cake and eat it too thing.The other thing I have read is the 6.0 is a gas hog.

I trust the input from here. It does seem to me there are a number of very knowledgeable engine builders.

Please and thank you in advance.

the LS engines are better in every single way when compared to a sbc. Better torque, better mileage, better power, better durability, everything.

[1Gary]

Maybe I would understand better if you could show me a example of the TQ curve for a LSx engine.

[ap72]

Originally Posted by 1Gary

Maybe I would understand better if you could show me a example of the TQ curve for a LSx engine.

there are a lot of them on Google.com, just type in "ls dyno" or something of that nature.

[1Gary]

I looked at this as a source:

GM LS engine - Wikipedia, the free encyclopedia

Many have a TQ peak at 4,400.Hummm..........

[1Gary]

Yes I know this is early on looking into this.It does have me wondering if Chevy by design built these not to gave much output early on and that is the reason for the good gas mileage.

[ap72]

Originally Posted by 1Gary

Yes I know this is early on looking into this.It does have me wondering if Chevy by design built these not to gave much output early on and that is the reason for the good gas mileage.

you have that entirely backwards. They have GREAT low end out put and that goes along with good gas mileage. I don't know how you could think they have poor low end.

Compare the 5.3l to one of the original 327's.

[1Gary]

I'm just looking at the 383 which by 2500 I'm well into the 4's in TQ and from the Wiki link I don't see that.In you honest opinion what is the single thing Chevy did to make these so much better?? Compression with aluminum heads in used. Try to remember I'm still in the discovery stage on these LSx's and I am seeing some aftermarket parts for them that are priced reasonable and some that are not.

[lmsport]

Chevrolet Performance #19259233
LS376/525 Engine
376 cu in (6.2L)
525 HP at 6300 RPM
489 ft/lbs TQ at 4400 RPM

[ap72]

Here is a dyno of a fully decked out 383 GM crate engine.

http://www.chevroletperformance.com/...M_12370838.pdf

[1Gary]

My TQ build 383 was 400 lbs at 2500 and just shy of 500lbs at slightly over 4,000.It is 375 at 4500.

LS3 I would have to be very lucky to find a wrecked 2008 Vett will a willing seller that didn't want a fortune for it.It's kewl to pick out a engine here,but the reality check happens when you go for the wallet to pay for it.

The thing I do is I look at the aftermarket for problem solvers in the parts they offer to understand what might be a issue.One common part I see is head gaskets for these or to be fair about it some of the LSx engines.Is that a problem??. Also in the aftermarket blocks some of the features they offer to maybe cure OEM design weaknesses,but there again,that might be just because of the extra stress of power outputs that I would never approach.
I did read about the limits of the OEM head design/rockers for enough space under the rocker covers for a high lift cam.It seems a good set of heads would be in the range of $1,800 to $2,000.

But I an still curious what you guys think was the one thing GM improved on the LS engines that make them perform as they do.

[johnnyg]

My dad has an '08 GMC Savanna 3500 w/ a 6.0, on a good day he gets 14 mpg.

[ap72]

Originally Posted by 1Gary

But I an still curious what you guys think was the one thing GM improved on the LS engines that make them perform as they do.

There are many things they improved, not just one. They improved heads, valvetrain, intake manifold, firing order, fuel and spark control, cooling, much more rigid block, better pistons and rings, etc.

If you're looking for just ONE thing then you'll never find it, the difference is because of many changes.

[1Gary]

Originally Posted by johnnyg

My dad has an '08 GMC Savanna 3500 w/ a 6.0, on a good day he gets 14 mpg.

That's what I heard while I have been investigating the LSx engines is the 6.0 are gas hogs.

[ap72]

Originally Posted by 1Gary

That's what I heard while I have been investigating the LSx engines is the 6.0 are gas hogs.

I can't figure out what's wrong with my 6.0L then, i get 18mpg on a bad day, 22 on a good one.