LS/modern motors vs the classic V8 sound . . . .

[mikedc]

Change my mind:
No LS (or other modern V8) ever sounds like a classic street motor. It either sounds like a modern V8 or a cammed-up race car. Why is this?


“It’s the alloy block & heads.”

I don't think so. LS motors (and Gen-3 Hemis) with iron blocks don’t sound old. Old motors with alloy heads/blocks don't sound new.


“It’s the firing order.”

It might be a small factor. But the gen-3 Hemi has the old GM/Mopar firing order and it still sounds modern. There were 1980s Fords & Corvettes with the LS order and they still sounded old.


“It’s the cylinder head design.”

Meh. LS, OHC Ford, gen-3 Hemi... these are wildly different heads but they all sound modern. A lot of customized heads have been tried on classic motors over the decades, and it never made them sound modern. Meanwhile the LS head resembles an old small block Ford.




“It’s the roller cam profiles.”


It's likely a big factor. But the correlation is mixed. The OEMs put roller cams in all 3 classic small blocks by the early 1990s. Gas mileage & emissions were big issues by then. Those motors were starting to sound modern but they weren't over the Rubicon yet.

Lots of classic motors have been given aftermarket rollers. Those are shaped for performance (just like aftermarket rollers for a modern motor.) But the sound difference remains.


“It’s all the factors together.”

Probably. I don't have a better theory.

But LS motors have been wildly popular for almost 30 years now. Is there a single one the planet that sounds like an old classic street car? I mean sounding like a SBC/BBC with vacuum secondaries and a brake booster. Not like a huge cam and 12:1 pistons and race bullet mufflers.

[Mr Nick]

Has anybody ever put a hydraulic flat tappet cam with "old school" specs in an otherwise stock LS? Wonder how it would sound.

[mikedc]

Has anybody ever put a hydraulic flat tappet cam with "old school" specs in an otherwise stock LS? Wonder how it would sound.

Yeah, I wonder.

But I don't think my question is answered unless the reverse works too. Show me a roller-cammed SBC that sounds like an LS.

Heck, show me a SBC that sounds like an LS after any amount of stuff done to it. Alloy parts, firing order cam grind, etc. Does that exist?

[Hotwire]

LS sound has measured exhaust pulses because the intake and exhaust tract are identical cylinder to cylinder. Air flows and bends almost identically through all 8 cylinders. Add the 5\7 cylinder firing order swap and it will never sound like a sbc\bbc. If you had someone make a head the same as an LS, intake with carbon copy runners and flip the firing order, you'd be hard pressed to tell the difference. You ever heard the exhaust note from a sbc with individually runner throttle bodies? It gets close. Get a straight straw, blow through it, get a bent straw and blow through it.

I've got too big headers, too big exhaust and I'm kinda partial to the sound of it.

https://youtube.com/shorts/NwyPq4JB3...G1pC2gsr1jJ7Y3

[Vimes]

Quite a bit probably has to do with block design. The LS block extends down a lot further and the oil pan is a big chunky structural piece. The SBC has a heavier block which will channel more firing sound out the cylinder bores, but still has half the crank hanging out of the bottom of the block with a thin tin oilpan. The pistons will act as a megaphone for firing sound to the bottom of the cylinder, so that sound going to hit a thin tin oilpan on one and a thick metal wall on the other. Metal intake vs plastic will also affect sound as metal and plastic will magnify and dampen different sound frequencies. The firing order swap, EIIEEIIE vs EIEIEIEI, cylinder head airflow (a great flowing SBC head flows as much as a crap LS head) and fuel induction methods also affect the sound.

The SBC is a nice sounding engine, but so is the LS. I prefer the higher power from the LS to a little bit of sound. Pipe that sound through a set of Classic Chambered mufflers and you won't care about a slight difference in the burble. I've put these on a couple of pickups with LS engines and an El Cabungo with an SBC, and both sounded outstanding.

[mikedc]

Equal-length intake runners -

I hadn't thought of that variable. Might be significant.

But I would expect a modern V8 to end up with uneven runners if it's wearing a carb intake (like a dual-plane). And the classic small blocks were getting modern dry EFI intakes in their final years, along with the roller cams.



Deep skirt block -

I doubt it's a big factor because it's only a modern thing on Chevys. Ford 390-428 and Mopar 383-440 were both deep-skirt blocks back in the day. Those sounded very traditional.



Classic Chambered mufflers -

Yeah I like those. They sound old-school and they aren't packed with fiberglass that blows out.



https://youtube.com/shorts/NwyPq4JB3...G1pC2gsr1jJ7Y3

Whoa, looks like it was breaking loose there!

[badazz81z28]

To the average person, they can’t even tell what you have. I had a LS1 in my 78 for years and everyone wanted to know if my 350 had a supercharger…..the sound is a myth. Most people are hearing the mufflers, which modern mufflers create all kinds of notes compared to old school flowmasters. I tried to place the guessing game at a local car show and it’s not easy. If you have a healthy, modified SBC with modern mufflers…I can’t tell if it’s an LS or not.

[mikedc]

To the average person, they can’t even tell what you have. I had a LS1 in my 78 for years and everyone wanted to know if my 350 had a supercharger…..the sound is a myth. Most people are hearing the mufflers, which modern mufflers create all kinds of notes compared to old school flowmasters. I tried to place the guessing game at a local car show and it’s not easy. If you have a healthy, modified SBC with modern mufflers…I can’t tell if it’s an LS or not.

Yeah, I realize that in the big picture.

Most people don't know/care. And mufflers make as much of an impact as anything.


I'm just very picky.

And I grew up on big-block Mopars, which is setting the bar pretty high in terms of sound.

[Hotwire]

I have people missing the mark on mine all the time. Locked out the timing to 22° at idle and have it set as low as I can without it dying on me. Can't really tell this is an LS out of a uhaul box truck with 150k on it.

https://youtu.be/0CaWnZVabJ4?si=-x-fEoYTWiVEmfg1

[badazz81z28]

As long as the mufflers aren’t those annoying crackling sounding, any V8 sounds great.

[JLMounce]

The inclusion of an X pipe makes a difference here as well. Many old school engines still rock true dual exhaust systems without a cross-over. Not only does this change the exhaust sound, but it has scavenging effects at the engine that will also have a tendency to change how things sound.

I don't think it sounds like an LS, but my 465 Pontiac also doesn't really sound old school to me either. It runs a pypes x with magnaflow mufflers on it.

https://www.youtube.com/shorts/BgHv_FwZQhk

[mikedc]

The inclusion of an X pipe makes a difference here as well. Many old school engines still rock true dual exhaust systems without a cross-over. Not only does this change the exhaust sound, but it has scavenging effects at the engine that will also have a tendency to change how things sound.

I don't think it sounds like an LS, but my 465 Pontiac also doesn't really sound old school to me either. It runs a pypes x with magnaflow mufflers on it.

https://www.youtube.com/shorts/BgHv_FwZQhk

A Pontiac without a Chevy motor? So they DO exist! My uncle swore he used to have one but he believed in Bigfoots and UFOs.


You're right, that motor does sounds pretty modern.

How is it cammed? I assume it's a flat tappet?

[JLMounce]

A Pontiac without a Chevy motor? So they DO exist! My uncle swore he used to have one but he believed in Bigfoots and UFOs.


You're right, that motor does sounds pretty modern.

How is it cammed? I assume it's a flat tappet?

It does have some pieces that would change the sound a bit.

It has KRE 310 cfm D ports which utilize a modern combustion chamber, a moderately large hydraulic roller cam that comes in at 240/248 @.050 on a 112 LSA. No 4/7 or 4/7, 5/2 swap on the cam, straight up traditional firing order. It uses a single plane intake which has more even runners than a traditional dual plane intake.

That combined with long tube headers, an X pipe and a more modern style Magnaflow muffler, is likely contributing to a modernized sound.