SBC vs LS physical size & weight?

I've seen LS's put into about everything and thought they must be pretty small, but the ad for the crate motor in this month's issue made it look more like a Big Block motor.

How does the SBC and the LS compare in physical dimensions and weight?

In reply to carguy123:

Not sure on the size details, but I've read about 100-150lbs lighter, depending on whether your SBC has iron or aluminum heads.

They are similar.

The height in particular can be varied more- the LS has both and oil pan and intake available that are low profile, and the SBC is often topped with a good sized carburetor and air filter.

Plus, the SBC is now really old technology, and the LS is superior in most every way (and cheap). Why use an SBC?

Is there a particular dimension you are curious about? I've got an LS on the bench I can measure.

The only real issue i ever had was the exhaust ports are higher than a traditional sbc, so when i put one into my astro van the header and floor pan were trying to occupy the same space. That was solved by putting a 350 in instead.

Generally the dimensions are very similar but you can set an LS further back with no worries of distributor to firewall troubles. I have put an Ls in place of an sbc in my 95 impala and my s30 Datsun z car using the same mounts the sbc used(with adapter plates) in both cars with no issues.

Any gen3 engine is lighter than a gen1 sbc with possibly the exception of the 99-00 6.0 lq4 which for some reason has iron heads. Aluminum heads and water pumps are standard on everything else regardless of block so you're dropping a ton of weight immediately without blinking. Stepping up to an aluminum block is pretty staggering. I am sure google will provide figures, but my datsun sits 1" higher in front with a 5.3 with iron exhaust manifolds than when it had an iron head 350 with light tubular headers. And to that my 95 impala is sitting an inch higher in front with no change but going from iron block 5.3 to aluminum block LS1

Patrick wrote: Generally the dimensions are very similar but you can set an LS further back with no worries of distributor to firewall troubles.

Not an issue on an SBF either, as the distributor is up front.

In reply to carguy123:

I just re-read your post.

They are similar in dimensions, but not in weight.

rslifkin wrote:

Patrick wrote: Generally the dimensions are very similar but you can set an LS further back with no worries of distributor to firewall troubles.

Not an issue on an SBF either, as the distributor is up front.

As long as the oil pump doesn't interfere with anything, anyway.

One nice thing about the truck GenIII engine (at least) is that the power steering pump and water pump snout (fan) are in almost exactly the same spot, so a 4.8/5.3/truck 6.0 is a direct drop in for a 5.0/5.7 Vortec. Which was probably Chevy's intention. The old SBC fan shroud works just fine and the old P/S hoses work just fine. Heck, the power steering pump and pulley are even the same. The only gotcha is that the right side motor mount bracket is in the way of the A/C compressor, but there are remote-mount A/C compressor setups now.

The iron block is a HEAVY MOFO though. Don't get me wrong. It's not a zillion times stiffer than the floppy old SBC by accident, Chevy achieved that by added a whole lot of metal. An aluminum block isn't all that much lighter than an iron SBC block!

Patrick wrote: Any gen3 engine is lighter than a gen1 sbc with possibly the exception of the 99-00 6.0 lq4 which for some reason has iron heads. Aluminum heads and water pumps are standard on everything else regardless of block so you're dropping a ton of weight immediately without blinking. Stepping up to an aluminum block is pretty staggering. I am sure google will provide figures, but my datsun sits 1" higher in front with a 5.3 with iron exhaust manifolds than when it had an iron head 350 with light tubular headers. And to that my 95 impala is sitting an inch higher in front with no change but going from iron block 5.3 to aluminum block LS1

Besides the aluminum heads and water pump, don't forget the intake manifold. A plastic manifold weighs a lot less than an aluminum one and weighs practically nothing compared to an iron one...

I am a little surprised that an iron GenIII weighs less than an SBC given that the block weighs about as much as a Chrysler 440's, but I'll defer to your greater experience in this field.

My research showed that the LS in alloy format was about 140 lb lighter than an old-school SBC.

What it also showed was that unless you are willing to run a truck engine as-is from the junkyard with the auto gearbox, they are a lot more expensive to use as swap fodder.

Manual gear mixers for the LS engines are crazy expensive. Parts to rebuild the LS are not cheap. Cost comparisons for rebuilds were done on the basis of Jeg's cost for rotating assemblies as the starting point of a rebuild.
By the time you are done mixing and matching intakes, oilpans and accessory drives, you have a lot of $$$ spent.

I don't know what it is about human nature, but there's something about engine weights that apparently inhibits people from using a scale... I see these threads all the time and people throw around numbers with no basis, like, how complete was the engine when it was weighed - IF it was weighed. How about someone post a picture of a complete LS engine hanging from a scale, else the stated numbers are all really squishy.

Aluminum LS1 + T56, seen on scale at 609#.

Ford 302 with carb not EFI and aluminum aftermarket heads + T5 = 475#, but that's a padded estimate based on parts-on-scale photos of the component parts.

I would offer to weigh my 302 lock, stock, and dipstick the next time I have it out, but I don't have scales that could swing that.

Anyway, Weight link

Freiburger did an episode with weights and sizes on a recent episode of hot rod garage IIRC. Let me see if I can find a link

EDIT: Found it.... not Freiburger though. size matters

I know that we see the LS in a lot of things, even a Miata and I know it costs a bundle of money, especially for the ancillaries like transmission. And this monster sized transmission does limit what vehicles the engine can go into.

My thoughts were that, based upon the picture I saw with no other engines beside it, that it was much bigger than I expected and therefore people were just talking it up because it was available rather than it was a small engine.

It appears I was about 50% right and 50% wrong. It is bigger than a SBC and definitely much bigger (physically) than a SBF, but it comes with modern day goodness and reliability and is readily available - albeit at a higher price tag.

My curiosity is appeased. I won't be putting it in anything because I prefer lighter and more of a scalpel than a big old blunt hammer.

Bigger brakes, bigger (and more expensive) tires, bigger gas tank, etc.

NOHOME wrote: My research showed that the LS in alloy format was about 140 lb lighter than an old-school SBC.

And an iron block is ~110lb heavier than an aluminum one.

I think the attractiveness of the LS is that it is small(ish), light(ish), and ready to go without too much fussing, right out of the crate. Sort of The Answer of motor swaps, even if it isn't the best budget option if money's tight.

I'll answer your question with another question. How long is a piece of rope?

fidelity101 wrote: I'll answer your question with another question. How long is a piece of rope?

What weighs more, a pound of LS or a pound of SBC?

JBasham wrote: I think the attractiveness of the LS is that it is small(ish), light(ish), and ready to go without too much fussing, right out of the crate. Sort of The Answer of motor swaps, even if it isn't the best budget option if money's tight.

And VS an SBF.... you can score 200hp 5.0 all day long but darn near every ls engine is 300hp out of the box save the early 4.8/5.3 which are 280-295(99 4.8 255?). And you can sneeze heads/cam at one and make 400.

They just work.

In reply to Patrick:

The brochures in 1999 stated 265hp for the 4.8 with the manual trans. I almost bought one and instead bought the Sonoma. Because I'm dumb.

I have a SBF in my 90 Foxbody. Nice engine, but not really a powerhouse by anyone's standards. Even with the standard (economically viable) upgrades you are only looking at about stock 5.3/LM7 power levels.

Not sure why anyone would bother swapping one into anything else, short of maybe some LBC weighing in at less than a ton.

I just passed on (to a friend) a ratty 02 LS1 / T56 Camaro convetible for $1900. One owner 167k with a slipping clutch and leaking pinion seal. Needs a top and cosmetics. Dings, dents and interior stuff but overall functional.

Saw it on Craiglist last night. Looked at it around noon today and followed my buddy home after calling him.

There are still deals out there.

SEADave wrote: I have a SBF in my 90 Foxbody. Nice engine, but not really a powerhouse by anyone's standards. Even with the standard (economically viable) upgrades you are only looking at about stock 5.3/LM7 power levels. Not sure why anyone would bother swapping one into anything else, short of maybe some LBC weighing in at less than a ton.

For my latest E36 track car swap the math worked out this way, after a year of careful price shopping in my local used-but-proven-solid motor market:

SBF & T5 with upgrades was 380 HP; 1.25 pounds per HP and $7.35 per HP (since I scrounged and installed the top end upgrades myself).

LS2 & T56 (stock, aluminum block) was 400 HP; 1.5 pounds per HP and $10.00 per HP.

SBF setup was 70 pounds less than stock E36 setup; LS2 setup was 70 pounds more than stock.

So I gave up 20HP, but saved $1200 for safety equipment I need, and actually improved the handling a touch instead of weighing it down a touch. But invested ridiculous amounts of my personal time hunting for deals on top end parts and installing them on the SBF, instead of having a nice turn-key Chevy package on day 1.

Plus I lived down the road from Flint in the 70's and I am just a Dearborn guy, plain and simple. Federal Offer of Refinancing Declined.

If God had wanted men to LS-swap track cars, He wouldn't have invented the Corvette.

SEADave wrote: Not sure why anyone would bother swapping one into anything else, short of maybe some LBC weighing in at less than a ton.

Front-sump oil pans swap more easily into some chassis. The inch shorter deck height adds some useful narrowness, too.

One neat trick with FB RX-7s is that if you rotate the crossmember backwards, a double sump 5.0 pan clears it and the center link perfectly.

Back from the grave.

Anyone have a width measurement handy, valvecover-to-valvecover on an LS?

Looking for an upgrade to the V8 Firefly, and it's rather tight with the Gen1.

SkinnyG said:

Back from the grave.

Anyone have a width measurement handy, valvecover-to-valvecover on an LS?

Looking for an upgrade to the V8 Firefly, and it's rather tight with the Gen1.

from here https://paceperformance.com/p-3990-engine-dimensions.html

has measurements of SBC/SBF, 4.3, LSA, new LT1, 8.1l,

also has this