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LS engine versus SBC throw down, who has the best torque below 3000, HP to HP

67K views 157 replies 14 participants last post by  Project89 
#1 ·
Started this thread to settle the debate of new to old, which engine of similar displacement has the advantage below 3000 rpm with similar HP.

Lets see who can come up with dyno graphs to support their views, I'll start...heres some 500 HP dyno numbers for a SBC.

383 from AFRs website, 195 heads 9.5:1 compression...nice street engine. Everyone has seen this kind of build before...pretty common.

Peak HP=506@6000rpm, torque=520ft/pds@4000rpm

https://www.airflowresearch.com/chevy_dyno.php

Whats important here isn't the peak HP, its the torque under 3000 rpm.

HP/torque=262/454 @3000 rpm

Next on the list is a similar LS3 built up by Crane to showcase their aftermarket cams.

LS3 x 3 – Comparing Three Performance Cams on the Engine Dyno - EngineLabs

Note the 500.9 HP version peaks at 6100 rpm with a peak torque of 488 at 4800 rpm.

More important to note the torque below 3000rpm, 238HP & 418ft/pds @3000.

This is where the SBC really shine folks...under 3000.

Alright who has a dyno sheet for an LS3 that tops that at similar HP, Im looking at you AP72.:thumbup:
 
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#2 ·
I would like to see a comparison between an LS-7(small block) and a 427 sbc with SB2 heads?
I cannot find my dyno sheet on my 434(yet,moved recently)but I dont remember my torque being much below 500 anywhere.My torque peaks at 4800 and hp peaks at 6500.
peak torque was around 550@ 4800
 
#3 ·
:nono:
I would like to see a comparison between an LS-7(small block) and a 427 sbc with SB2 heads?
I cannot find my dyno sheet on my 434(yet,moved recently)but I dont remember my torque being much below 500 anywhere.My torque peaks at 4800 and hp peaks at 6500.
peak torque was around 550@ 4800
why would you want to even see test of a 427sb with heads made to flow the best and have the best port velocity on a 357 at 9000 rpm..


can we test an over cammed engine also..
 
#5 ·
Chevy LS3 Engine Camshaft Comparison - GM High-Tech Performance Magazine

there's an article with various cam swaps on a stock LS3. Most of them are too much for the original argument- as they fall in the 525-550hp range but it shows what can be done for about half of the cost of the 383.

To be honest I'm having a problem finding an engine dyno chart with an ls3 at 500hp. Nobody seems to be aiming that low. There are several with that at the wheels but it doesn't provide a good comparison at all. A bone stock LS3 with headers and a tune will get very close to 500hp- stock cam and everything.

It'd be easier to compare 500hp "350's" as there are a lot of ls1's with 500 flywheel hp. Or even "327's" with the 5.3L.
 
#6 ·
I think you answered your own questions. LS motors make their max torque and horsepower at a higher rpm then a SBC. So one can safely say LS motors are higher revving engines then SBC. I have not done any LS motor builds yet, but have been reseaching them and I noticed right away that most people are using higher stall converters and lower rear end gearing with LS motors. To compare torque of a SBC and an LS motor under 3000 rpm would not be fair. They are 2 different animals.
 
#7 ·
he didn't answer anything- he stated a hypothesis. That's the point of the thread, to show how the sbc doesn't do anything better- except maybe use the engine mounts you already have laying around.

I'll be the first to admit though- he did put one hell of a qualifier on it. It's hard to find LS engines built exclusively for low rpm as there really is no reason to.

If you're going to bother to put money into an LS engine you're going to want some returns, most people don't equate "power" with anything below 3,000 even though that is where most of your driving is done.

It is a well thought out question to ask. His hypothesis is wrong, but finding supporting evidence will be tricky.
 
#10 ·
Through deductive logic it seems GM's intent in the design of the LSx engines has always been a engine to develop a power curve in the upper rpm ranges and that is especially true when you consider those engines mated to the T56's first gear. Correct me if I am wrong.

What got me off the search/research on the LSx engines was if you spin any engine up into the higher rpm ranges,the parts wear faster.That just kind of make sense.And yet the LSx engines are a attempt at a "cake and eat it too" situation given normal driving not tapping into the power curve thus giving better gas mileage along with the electronics attached to it.

I do think,because of the above,the first gen SBC's will provide a broader torque curve at a lower rpm range over the LSx engines at a price of lower mpg.And I do think the first gen's parts will last longer.
 
#12 ·
these engines also almost always come with transmissions with double overdrive gears and cruise along at or below 2,000 quite happily. And the 1st gen parts do NOT last longer, not even close. As long as you change your oil you can expect 500,000 miles from any of the LS engines without having to even change the spark plugs. They just keep going and going and going.


Also, there is a hell of a lot more to parts wear than rpm- in many cases running it at too low of an rpm causes damage, and look at all of the 4 bangers out there- most of them cruise at 2500-3000 rpm and most of them show very little wear at 200,000 miles.

Also, don't say they're attempting to develop a power curve at higher rpm- their design screams otherwise. They carry the power very well, but they are not "designed" for high rpm. Keep in mind the Vortec 5.7L gen 1 predecessor (arguably the best gen1 sbc) peaked at 350ftlb at 2800 rpm, the LT1 (the other contestant for best sbc) peaked at 335ftlb.

The gen III, 5.3L was rated at 338ftlb- that .4L less displacement and the same peak torque.


Look at this: LS3 x 3 – Comparing Three Performance Cams on the Engine Dyno - EngineLabs

that is a BONE stock LS3 with headers. then they add a baby cam, then another baby cam, and yet another baby cam- it takes very little duration to make these relatively big power numbers. And this is with a stock engine. the cam and valvesprings were changed- that's it! Your total investment is a little more than just a set of AFR heads.


I cannot make a big enough point that you are comparing fully built sbc's to used mostly stock LS engines- and the sbc's are still loosing.

If cost is a concern- you go LS
If power is a concern- you go LS
If durability is a concern- you go LS
If mileage is a concern- you go LS
If bolting to your existing engine mounts is a concern- you go sbc.

BTW, this same argument can be made for Ford and Chrysler, though their newer stuff comes at a higher cost.

Don't for a second think that you can somehow do better in your garage than the engineers for the "big 3" can do- there's a very good reason they all updated their engine platforms, and it wasn't to simply piss money away.
 
#11 ·
A lot of the LS glamour comes from it's CNP ignition system,fuel system & tuning.Powerwise & milage.Ppl that have converted them to carb have been for the most part disappointed.The engines themselves while being better in some sense aren't what they are made out to be w/o all the other amenities.
 
#17 ·
Those baby cams you refer too are similar to a GM hot cam. Although the lift of the LS cams are waaaay higher.

You want to take a stab at finding a 383 SBC with that cam that under performs the LS3?

Its not pretty.:D

I won't torture you AP, I like the LS engines as much as anyone else.

The fact is, the open chamber of the LS engine family was designed for emissions and efficiency. The SBC has a lot of quench in the closed chamber, which boosts torque...also poor at emissions and efficiency.

The LS engine torque peaks are at higher rpms than a comparable HP SBC...because of the open chamber...that is simply fact.

As for the cost factor I have yet to find a decent deal up here on any LS engine that didn't need a complete overhaul, the heads don't last any longer and any late model FI 350 has similar bore wear at the same mileage...fuel injection is what reduces bore wear...not design.

Not to mention good luck finding a used LS3 motor for the same price as a rebuilt crate SBC with AFR heads and stroked...that argument is simply not true.

Used LS3 Engine | eBay

383 Chevy Engine | eBay

Where are you finding LS3 engines for cheap, I wanna buy one!
 
#18 ·
You just need to shop around, a new LS3 is right at 6K, I've seen used in the 1k-3k range depending on mileage. Also, I use that example only because you used a 383- if it were my build I'd just go with a cheap 5.3L truck engine- $500 bucks ll day long, less if you wait for a deal.

If we compare a 5.3L to a 327 or a 350 the power per dollar is MUCH better.

As for wear and head design, I don't think you understand what is different on the LS series so I'm not going to go down that road- one point I cannot stress enough though is that the head flow is NOT the biggest change. Everyone on this forum is obsessed with head flow but there's a hell of a lot more different in the LS engine than the valve angle and flow numbers.
 
#19 ·
#22 ·
327 Small Block Chevy Engine Build - Chevy High Performance Magazine All Pages

that link worked, I presume its the same article.

as for a comparable build, I don't think anyone has ever put 10K in a NA 5.3L- a lot of guys have put 2K into a turbo 5.3L to make 700+hp though.

No one would attempt a build like that on a 5.3L as its pretty pointless.

I'm not really impressed by the power on that build either to be honest- 10K could have been much better spent.
 
#26 ·
$500 used 5.3L
$700 for a cam and springs
$100 for pipe and flanges
$300 for injectors
$400 for complete MS system or you can use a stock ECU- your choice
$500 ebay turbo

$2500 total for 700hp+ on pump gas. Hell throw in a fuel pump for another $150 if you want. Those are high estimates btw, and everything is new except the original engine.

If you want to keep the same recipe you can also do the same with an LT1 or TPI engine, just expect to drop off about 100hp.

Its not new, its not shiny, but it makes more power, uses less fuel, and is more durable. You can spend your money on new and shiney and build a high end turbo LS(whatever) for 10K as well and maybe get yourself another 2-300hp, but how in the hell are you going to keep it on the street?
 
#27 ·
Thats a grenader engine you cant let the "dumb-butt" guy down the road drive.The ls-5.3 will make more power than the sbc with stock GM heads.
the plumbing will be similar(not free!or $100.00)
dont need the $300.00 injectors and a used 350=$50.00
buy a fat roller cam
take that $750.00 you saved and buy assault chinesium heads that out flow 5.3 heads
winner SBC
 
#28 ·
You'll need injectors even on a 350, and good luck finding a good running one for 50 bucks. The cam cost is the same, and I agree the assault heads give you a better starting point than any oem head. I assumed with the 100 bucks that you can use a wire welder. With the assault heads the sbc will fair a lot better, still has worse oiling, cooling, pistons, cam core, rockers, etc etc but at least it'll get closer to a 5.3l, and you're only looking at the extra cost of a set of heads.
 
#31 ·
Heres a 5.3L build with aftermarket heads even!! 436HP though.

Heads - Cam - 5.3L Bow Tie Builds Mild To Wild - Chevy LM7 Engines - Truckin Magazine Page 2

Heres a 327 build, 441HP with a dual plane intake...460HP with a single plane.

Hooker Super Comp Headers - Chevy Small-Block 327 - Super Chevy Magazine Page 3

Check the HP at every 1000 rpm, it loses at every point and can't stretch past 6500 rpm.

I don't buy the cheaper to build argument, you can't compare used to rebuilt and your pricing is way off even for used parts.

I keep putting up superior numbers for the SBC, where is these fabled LS numbers that put the old school motor on the trailer?
 
#32 ·
1996-2002 L31 350 255hp@4600rpm/330lb/ft torque@2800rpm
1999-2007 GM trucks(GMT-800) It took a few years to overtake the L31 Vortec 350's torque output.
1999 LM7 5.3 270hp@5000rpm/315lb/ft torque@4000rpm
2000 LM7 5.3 285hp@5200rpm/325lb/ft torque@4000rpm
2004 LM7 5.3 295hp@5200rpm/330lb/ft torque@4000rpm
2005 LM7 5.3 295hp@5200rpm/335lb/ft torque@4000rpm
2005 L33 5.3 310hp@5200rpm/335lb/ft torque@4000rpm (alum. block compression from LM7;s 9.5:1 to 9.9:1, Max. valve lift increases from 11.6 mm on the LM7 to 12.5mm. on L33, 243 LS6 head design used, but with non-sodium valves.

then in 2007 the 4.8 and 5.3 GEN 4 engines used in the 2007-2013 GMT900 trucks the LS6 type heads are used on all 4.8/5.3 GEN 4 engines, which accounts for the elevated torque peak.
2007 LH6 5.3 GEN 4 315hp@5200rpm/338lb/ft torque@4400rpm
2008 5.3 LC9 GEN 4 315hp@5200rpm/338lb/ft torque@4400rpm on gasoline
326hp@5300rpm/350lb/ft@4500rpm on E85 fuel

These GEN 3 engines are getting to the point where low rpm torque is lacking for truck use. To combat this the GEN 4 6.0/6.2 engines start using VVT(Variable Valve Timing) to try and preserve low rpm torque, while still providing upper rpm power. The 6 speed auto which is used behind many of tehse engines, also geatures a 4.03:1 1st gear ratio in order to help with the low rpm torque shortage

The GEN 5 Vette LT1, and L83 5.3 and L86 6.2 engines used on the 2014+K2XX platform got Direct Injection which aids lower rpm torque significantly.

It's interesting to see how GM has kept adding power and what they are forced to do in order to supply enough low rpm torque to satisfy towing
needs, while at the same time, providing that all important power number that sells vehicles.

peace
Hog
 
#34 ·
Ok lets go up the other way, an LS7 is similar to a 434 stroker. Heres a 770HP SBC dyno sheet, forget torque below a certain rpm...lets talk torque and HP above 5000 rpm.

I won't cherry pick an LS7 dyno sheet to make it look bad.



If the argument is the LS motors aren't typically built to lowly 500 HP levels, lets see one that tops this rpm for rpm....no holds barred any head but it has to NA.
 
#36 ·
I know but at over 700 HP I think we have left the "streetable" class behind.

Post up your dyno sheet finds, the more the merrier.
 
#37 ·
700hp na LS7

730hp streetable ls7, stock short block, worked stock heads, cam, the basics. Runs on pump gas.

Interesting that you pull out a full out race build that likely doesn't have one stock part, heads are likely far from the factory layout, and can't run on pump gas... and its within spitting distance (about 5%) of a mostly stock LS engine.

BTW, I didn't cherry pick that one, just the first one I found on google.


There are 1,000hp NA "sbc's" (have to use that term VERY loosely) but considering they share nothing in common with the basic 350 that everyone is so familiar with I don't see what it proves. The fact that you are a cam and header swap away from 500hp on a 5.3L or 575hp+ on anything over a 6.0L says a lot. The best sbc (LT4) at 5.7L can't claim the power of a 5.3L engine with the same very basic parts (cam and headers), compare it to the oldest LS1 at 5.7L and the LT4 is toast, hell in many cases it can be beat with a 4.8L. Down almost 20% in displacement and it makes the same power with a much smaller cam.

I understand the sentimental nature many people here have for the sbc, but you're argument is the same as what people claimed when Ford switched to OHV, that in some way the flathead was superior.
 
#38 · (Edited)
AP:welcome:
"same as what people claimed when Ford switched to OHV, that in some way the flathead was superior." Glad you were there when that was going on !! To tell us that LOL I must have been too young to remember that LOL:thumbup:

Shows how young you are :mwink:

the Flat head had been converted by Ford to overhead valves first it was in trucks and called the Arden designed by Zora Arkus-Duntov and his brother Yura Arkus- Dontov. and it was a Hemi !:p

A little Nostalgia : Ardun Overhead Valve Hemi Head
Ford Motor Company had a rather large contract to furnish trucks to the City of London. There being a difference in the way horsepower was rated in the US versus the UK, the engines were under powered and Ford was about to lose their contract. FoMoCo hired a young consultant engineer, a Russian emigrant, to address the problem. He designed an OHV head adaptation for the flathead. Later he was to achieve fame at Chevrolet as the father of the Corvette.
The overhead valve engine was so good some were used in the states for fleets of heavy trucks(but they are very rare!) Very shortly after that ford came out with their new engine design.:thumbup:

Sorry to borrow this thread for a minute LOL

A little more: My favorite small block!! With mostly stock parts! Vinnie knows this one :D!!! I built Many over the years And still do. But with bigger cams and Tunnel rams! The one in my car is 475 HP, The one for my wife is 435 HP.

TECHNICAL DATA
VIN number 124378N411100
Build Date 04A (first week of April)
Color Corvette Bronze
Interior Code 712, black standard
Car Shipper Shipped on April 11, 1968 to Ammon R. Smith Auto Company, York, PA
Engine Data Cubic Inches, 302 LOL:mwink:
Cylinder heads #3917291, completely stock, no porting allowed!
Stock rocker arms & valve springs
Intake 302 aluminum intake, casting #3917610
Carburetor Holley, #4053, 780 CFM 4bbl
Camshaft Crane, .480 inches lift, 272 degrees duration, valve lash, .016-.016
Pistons GM 302, .030″ oversize
Horsepower 456 @7700rpm documented
Rear Tires 9″ x 30.0″ Hoosier’s
Rear axle & ratio 12-bolt, 5.57 Richmond Pro Gears
Clutch 10 inch, three finger from Advance Clutch Technology
Shift Points 8200 RPM
BEST ET 10.80 @122.30mph

most of you know this car!!
Again I'm sorry for stealing your thread for a minute:thumbup:

This thread is great keep it going LOL I'm an old small block guy:thumbup:

Jester
 
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