"427 engine sound you can feel"

[petek]

From a strictly resonance standpoint things like the volume and shape of the intake and exhaust ports (as well as cam overlap) will have a large bearing on how the engine sounds. (Imagine a pipe organ.)

There is a LOT that goes into the mix to produce the sound you hear. Listen to a 5 liter Ferrari, Porsche, Chevy, and Ford. All are the same size, but each develops the engine size a different way and producing a different sound.

[xlr8or]

Thanks Bill I try to keep things on the lighter side.

Your tunnel port does not sound good. It sounds GREAT!! Although a little on the quiet side.

Did you ever notice how the big blocks set off more car alarms when driving around town?? Thats the engine "feel"

[Charlie]

Bill, I believe you when you say your 427 sounds great at idle, even with a mild compression ratio. If my theory is right, then you are still getting alot of cylinder pressure because of the long rod-to-stroke ratio parking that piston at TDC longer. If the beer hasn't killed my memory totally, then those kinds of engines like long cam profiles, as you mentioned the FE likes. I will check a few books at home which talk about long-rod engines to see if that is correct.
But lets differentiate between loud engines and powerful pulse engines. My car is loud, it routinely sets off alarms all over this city, so it must be producing some pulse waves. But it is a far cry from pulse producing like a truly powerful engine. Those little riceboy cars are loud, but their sound couldn't set off an alarm if they tried! What Mike made me realize is that the pulse we feel is a pressure wave. It has to be produced by an energy source like a cylinder explosion. The greater the energy under that pressure peak, the greater the pressure pulse we feel in our chest. I believe that is the true cause-effect. All the various engine factors, like cam profiles, compression ratios, breathing efficiency, etc. all effect how strong that pressure peak will be, and ultimately, how powerful the engine is. The difference between my engine and a powerful 427 is the amount of energy in that pressure wave.
The noise we hear is a pressure wave too, with all the various harmonics of the engine and exhaust thrown in too. In the case of the 427, it is a sweet noise. According to you 427 owners, the harmonics all add up to one sweet note, and I believe you.
But I am a bit sceptical that you 427 guys can pick out a 427 from a strong 460 or 429 by sound alone. So I issue a challenge. If you can get a bunch of you together with different engines, then blindfold someone who insists they can tell, and drive the different cars past him so he can pick out the 427 powered cars. Then we will see. Some interesting betting could come of it.
Let me know how it turns out.
One last question. . . does an aluminum block 427 sound the same as an iron block one?
Charlie

[petek]

"...does an aluminum block 427 sound the same as an iron block one?"

Now that's a real good question! Assume identical intake and exhaust systems; I'll bet the two sound virtually identical as I doubt that you'll get much difference in sound though the block itself.

[wilf leek]

Originally posted by Turk


I am sure it is the firing order....

WHOMP, WHOMP WHOMP

Weeeeeeeeeee!

You can imagine which one is which.
TURK

Turk - you know that I have always had respect for you, but now you have taken it to new limits.

Admitting, on this public forum, that you lose bladder control after hearing just three firing strokes from your new engine - well, it takes a great guy to do that. A true petrol-head.

Respect.

[Charlie]

I want to apologize to the members of this forum, especially you lucky 427 owners. I am much too much of a greenhorn to be issuing challenges, especially over something I know so little about. I admit I know little of the 427, except that I want one real bad! I am a born sceptic. But just because I can't tell the difference between the sound on the big engines, doesn't mean that you guys with LOTS more experience can't also. I will just have to accept that and wait till I am lucky enough to have one of my own and see if someday I can tell the difference too. Until then, I stand in awe and wonder. Again, please forgive my brashness.
I will go stand in the corner now and shut up.

[rdorman]

If a 427 and a 351 are idlling in the woods, and no one is there to hear them, which sounds better?

Rick

[GeorgiaSnake]

Thanks Wilf I thought Turk was beating his cat again

[bmalone]

Hey Charlie, I thought it was a good question. No thread degeneration, either.

[walt347]

After having read this post I feel very unhappy ..... NEVER heard the sound of a 427 !!! Can anybody e-mail me a sound file (.wav) or an URL (link) in the web ? My e-mail is:

walter@wrothe.ch

Cobras with BB are really difficult to find in Switzerland ....

Many thanks,

Walter

[Cracker]

I have 427 SO and just about every time I stop for gas at least one fella says "thats sounds like a 427). I can't compare because I haven't yet met up with our Atlanta area crowd to hear other engines. Heck, I've never heard a 351/302/460 or even another FE for that matter. All I know is that it is the most glorious sound a muscle bound car could ever have. Gives me chills just thinking about it.

[xlr8or]

Walt and Cracker,
You should both go the Fling next month.
There will plenty of variety to hear, see, feel and envy.


Scott

[petek]

Can't give you a 427 but here is my 351 (MP3 format): http://www.birch.net/~petek/temp/cobra.mp3

[A Snake]

This is a good thread! First one I 've read in a while that didn't go off to Jones's.

I think that between the various posts outlining compression, cylinder head design, cam profiles, fireing orders, etc., the nail got hit squarely on the head. It is all of the above with compression that hits you like a hammer being the big dog.

Why does a 351C sound like a BB Chevy? Easy. Canted valve heads with very similar port configuration. I've owned both. The only difference I could discern was the pitch of the BB Chev was deeper. The general sound was virtually identical. I once had a sand drag Bronco, with a Boss 351C in it. I can't tell you how many times I got asked if I had a rat motor under the hood.

The FE sounds like no other engine I've ever heard and I attribute that to a cylinder head design unlike any other engine. I exclude the Cammer and TP, because they each also have a sound that is uniquely theirs.

As to could I pick out a MR or HR 427 S/O out of a crowd blind folded? In a heartbeat!!

Want a real laugh? I parked My Contemporary (w/11:1 427 S/O) out side of a restaurant once, out of sight of the front door. When I got inside, I got asked if I was the guy who just rode in on the Harley!!! Musta been those Butler mufflers! There weren't any Harley's on the lot!!

Al

[Turk]

Walter,
It would take a high speed connection to send a sound file of a big block. You know the sound is soooo large.

Yet, anyone should be able to attach a SB sound without any difficulty. most are about 2 or 3K long..

TURK

[427 S/O]

I really like the sound of a SO at idle when it 'spits'.

[Excaliber]

To keep the size of the sound file smaller with the Big Block, just rev the engine up to something over 3,000 rpm. I love the sound of a rod coming through the block at the end...........

Turk,,,bite me! LOL

Ernie

[walt347]

Turk, mmmhhhh..... I'm not an expert in computers, but I always thought that the size of a sound file depends on its length and not on size of the engine. My questions is: "Does it take so long to rev a 427 S/O up to 6'000 rpm ?"

Lol, Lol, Lol, take care ....



Walter

[misfit41]

this is good,,I have been in love with the sound since the late 70's,I helped pit a local racer here,,short track,arca,a little winston cup,{he still races 427's}I can remember being behind the stands when the cars were hot lapping,,or qualifying,,there were many 600-700 hp big block chevys,and hig dollar bow ties {this is still going on by the way,it was easy to tell when the 427 was on the track,I am not sure we could explain the difference,since so many factors could effect,,actually the fe motors have their own sound,I think the 427 difference may have something to do with big cubes,derived from a huge bore and fairly short stroke,,but the head ports as well as valve size could mean a lot too,,my 427 sounds wicked,,but the stainless side pipes make it sound a bit tinny,,they have to go,,my motor isnt close to the 14-1 compression motors we ran then on alcohol though,,427's are one of those things I wish i had never experienced,,now there is no giving it up,,sort of like a strip cluib,,heh BTW,,to whom ever ask,390,427,428,406 etc use the same rod lenght,,428 has a 3.98 stroke compared to 3.78 on the 427,but the wrist pin is closer to the top in a 428 piston,,
keep it coming guys,,Tim

[Charlie]

I asked about the rod length. I looked it up and the 390, 427 and 428 all share the same rod length. Some may ask, so what? What this does is give the 427 a longer rod to stroke ratio. I'm no combustion engineer, but I have read that you need to park the piston at TDC for a relatively longer period of time so that the cylinder pressure has more time to fully develop at high rpm. It takes time for the flame front to develop. I'm pretty sure that all the competitive racers are using "long rod" engines these days to get that extra edge. The 427 has a slight edge in this way by design. Of course, that does mean you sacrifice some low end torque, where the longer stroke and lower rod to stroke ratio of the 428 will shine. Like most things, it is a balance. If you park the piston at TDC too long, then the pressure peak starts to fall off before the crank has rotated past TDC far enough to allow the leverage of the crank throw to work. That is why the long rod engine won't do as well at low rpm.
Charlie