## Small block Chev (classic) exhaust notes/tuning physics etc

Somewhere in a dark corner of the "internet" lies a video of somebody that somehow crossed the leads from the header pipes so instead of all the primaries going into one collector some go into the other side collector........that produced a very exotic sound.

Can someone tell me a little more about his process?

180 degree headers are NOT going to fit in my car so I am starting to try and find other options that will make a higher pitched more exotic (Ferrari like etc) sound (not rice...).

Working with a 327 Chevrolet. I love the sound of muscle, the car is not muscle and should not sound that way, or to the best of my ability to capture it. The complete setup of the engine.
4.040 bore (3.25 stroke) inches (we are going to magnaflux the block to see if it is capable to go to a 4.060 bore)
team g intake single plane manifold
jegs 195cc intake port, 64cc chamber heads aluminum strait plug(these heads are getting worked and will be put on the flow bench soon)
the cam will be setup for the intake/heads/headers that are selected in the end result. The cam will put the engine in the 3000rpm-7000rpm range and a redline of 7500, albeit will be designed around the intake/heads/headers flow etc.
The compression will be at 10.5:1, so as to utilize pump gas.
Forged crankshaft (small journal block, two bolt) cross plane style crank shaft I am not going to swap in a 180 crank (flat plane) as per Ferrari spec much too much work and $$to do such a thing. I have yet to decide if I should pony up for 6" rods or just stay 5.7" rods the rockers are at a 1.6 ratio. The engine is designed around the fact that I wanted a specific rpm range, the car is very light and tires are very limited. The max tread width I could find in the max rim size available was 8.5 inches. The section width of the tires are 245mm. The rim itself when measured end to end was 240mm. The car will weigh in at about 2800lbs. The donor car is a 1978 Datsun 280z five speed which is going through a sbc v8 conversion. The drivetrain (axles, transmission, and differential) that are available can hold to the hp (which I realize is tq(rpm)/5252). So the rpm of the motor has been raised to the 7000rpm mark to best match the transmission ratios and differential ratio as well as to produce more peak hp than low end tq. Too much tq will just cause the tires to spin and cause premature part failure. ratios 1st gear 3.06:1 2nd gear 1.63:1 3rd gear 1:1 4th gear .7:1 (more of an overdrive) Differential 3.545:1 The tires are 245/50r16 at a speed rating of 97w. The speed rating limits the tires to 168mph. One issue that I have found is header clearance. So I need to know what header type is going to best suit this as well. From my understanding "shorty" tubes with a larger diameter (about 1 and 3/4 of an inch) would be beneficial to the rpm I am going for rather than long tube headers. The kit (jags that run) comes with sanderson block hugger headers to avoid the steering shaft that is in a inconvenient location. I found this on the Ferrari forums. "An American V8 with a cross-plane crank doesn't fire alternate banks consistently. The firing order means that you sometimes get successive exhaust pulses into the same manifold. In a dual exhaust, this means inconsistent pressure pulses in the two sides. Look up "beat frequency". When you have two frequencies that are almost -- but not quite -- the same, the difference causes a low frequency pulsation (beat frequency) that gives the American muscle car its distinctive low frequency rumble. The same thing happens in twin engine aircraft when you don't "synchronize" your props -- the rpm difference between the two props makes for a low frequency throb you can feel as an intermittent vibration. With pure alternate bank firing, the Ferrari engines have identical pressure pulse rates into both exhaust manifolds, so the exhausts are "synchronized". After that, it's just a matter of tuning the exhaust paths. So, no, a Ferrari type exhaust on a cross-crank engine will not replicate the Ferrari exhaust note. Some newer GM V8 engines have cross-connections between the exhaust sides to reduce the exhaust "rumble"." I would like to know more about the cross-connections that are done on newer cars if you guys know anything about that? Also from my understanding (this may or may not be true) a "x-pipe" exhaust with chambered mufflers will help create the more European sound that I am looking for as well as help with the exhaust pulses. Any thoughts there? Are there any other options I may consider? Lets please stay on topic and factual please. Any educated answers would be greatly appreciated. An example of the sound (which btw I have heard corvettes (cross plane cranks) as well as the larger v8 bmws (cross plane cranks) create, I just don't know enough about exhaust to know what is done to create this as well as keep performance as well. Hence the posting. Link of a Ferrari 348 engine sound http://www.youtube.com/watch?v=g2Cxm...ain&playnext=2 If there is more information needed about the car I will do my best to provide the information. Fayt~  PhysOrg.com science news on PhysOrg.com >> Hong Kong launches first electric taxis>> Morocco to harness the wind in energy hunt>> Galaxy's Ring of Fire  Short of a flat plane crank or 180 degree headers, no, you will not get the even exhaust pulsing you are after. An X-pipe will be the best you can do. Since you have only a 3.25 stroke, the 5.7s are fine; a redline of 7500 means better rods anyways and I usually put in 6.0s when upgrading. Have you considered using a Supra turbo motor/drivetrain? That would give you the smoother sound and have more than enough power.  It is extremely more expensive to work with import motors than a sbc. The sbc is the least expensive motor to build. I also already have about 2300 into the motor. I am looking for a 500 plus hp engine that could produce and even tq curve through the entire range so I needed the proper amount of displacement as well. I was going to do a 283, but the piston availability was very small and expensive compared to 4 inches or more. It was less expensive to build a 327 than the l28 that the car came with. I was going to supercharge the 2.8 L6 the car came with but mega squirt is not my friend. I like to try and keep the fuel delivery process simpler with a carb. -------------- Could I take shorty headers and connect the primaries necessary? One big problem people have found with 180* headers is that the length necessary before the collector limits the usable rpm range. ## Small block Chev (classic) exhaust notes/tuning physics etc Better set your sights a little lower, a very good street 327 will be doing well to top 400 hp. The long tubes are needed to cross over to the other side of the engine to produce the even pulsing and there aren't any shortcuts.  Quote by mender Better set your sights a little lower, a very good street 327 will be doing well to top 400 hp. The long tubes are needed to cross over to the other side of the engine to produce the even pulsing and there aren't any shortcuts. You are incorrect about the 327s maxing out at 400hp. As just an example. http://www.chevyhiperformance.com/te...d/viewall.html The heads I have are knock-off afr 195cc comp heads.  http://www.youtube.com/watch?v=RkVgD5l5EOo v8 m3 - these have a cross plane crankshaft. Love this sound. I was under a 545i today (same engine) they use shorty headers and a x pipe. I don't know what the deal is with the muffler though. I don't know if the ITBs that they run would affect it that much really, because I have heard vettes sound like this. m3 Header http://www.porscheboost.com//images/...58168_11-1.jpg Does anyone have any info on this?  http://www.corvettegarage.com/produc...-corvette.html Check the sound bites out  Any chance that you can get a camshaft ground so that the firing order changes to cause alternating banks of cylinders firing? ...Looked into this further and it appears not to be possible due to the dual-plane crank. Never mind  Quote by faytmorgan You are incorrect about the 327s maxing out at 400hp. As just an example. http://www.chevyhiperformance.com/te...d/viewall.html The heads I have are knock-off afr 195cc comp heads. I never said they maxed out at 400 hp, I said a good street 327 would be doing well to top 400 hp. The most recent SBC in that displacement range that I built was a 343 that made 664 hp at 7200 rpm; quite civilized in behavior considering, and some people might be tempted to put that on the street but it was built for a local GT-1 racer. I'm building him a 422 for his street car that should make close to 600 hp but be much nicer to deal with. Still will be on what I would consider to be the ragged edge of being streetable though. As per the article, a 254/260 cam hardly qualifies as a street cam for most but it depends what you're willing to live with.  Quote by 2milehi Any chance that you can get a camshaft ground so that the firing order changes to cause alternating banks of cylinders firing? No; the crank dictates the movement of the pistons, not the camshaft. Unless equipped with a 180 degree crank ("flat" crank) or 180 degree headers, the exhaust will have the distinctive V-8 sound. ETA: seems you already found that out.  Recognitions: Gold Member What is wrong with the sound of a Chevy small-block? Spend a day at the strip and watch those 283 wheel-standers run and listen to them. Who needs$$ foreign cars?
 Some people like the smooth sound of equally spaced pulses: http://www.youtube.com/watch?v=vEYOx6u00f4 I'm one of them.
 "To replicate the Ferrari exhaust note exactly will take 1) Single plane crank with shorty equal length headers and a short overall length exhaust system, (shorter length is higher pitch). 2) 180 degree headers of equal length, as short as possible with the primaries to retain as much high pitch as possible along with as short of overall length. This will get you 90% there. 3) 8 into 1 headers all primaries being equal length, again as short as possible. 4) Some mufflers such as Spintech have a unique of absorbing the tones that give the domestic V8 that old boat drumble giving a more distinct crisp smoother "raaaaaaaap" to the exhaust note with a hint of off beat rumble. Listen to youtube sound clips of c-5 &C6 Vettes with spintechs for an example. Not positive about diameter and it's effect on exhaust note/tone. Pretty sure smaller equates to higher pitch due to higher velocities, if that is indeed the case, finding that balance of small but so small it is restricting. Spintech is a chambered design, I dont recall if they offer a Stainless version, if so Stainless will last much longer than mild steel, 15+ yrs. Not sure how long the mild steel versions would last, 5 years? So shorty equal length headers that as soon as possible go into one collector, an x pipe, and then to a chambered designed muffler. Do muffler lengths and tips change the pitch? Im not sure, I would suspect it would, but only slightly. Most likely would the tone coming from the shell of the muffler/exhaust as it rings from the sound traveling within, most likely noticeable only standing right next to the muffler if..."