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Exhaust choice for a V8 swap


Guest Anonymous

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Guest Anonymous

I am currently planning a 240 or 280z v8 conversion, and I was wondering what you guys have generally used exhaust wise. I would be using a 350 chevy, and probably shorty headers. Is there a pre-made exhaust alternative to fabricating the whole darn thing? Thanks for the help!

 

Steven cheers.gif

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Guest Anonymous

You might want to do a search in the archives under 'Exhaust', I think you'll find loads of info previously discussed. There is not 'kit' for the V8 cars, its a custom deal all the way, and as someone who has built 2 systems both of which were to low, I can only suggest bitting the bullet and have a pro put a system on for you unless your a muffler guy. Just a suggestion, doing it laying under a car on jackstands takes alot of time, patience and swearing. ;)

 

Regards,

 

Lone

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Wow, there are MANY different approaches to this one. Most people here seem to do a 2.5" dual into 3" single setup with a 3" muffler in the rear. Some add a muffler in the tunnel too.

 

Block hugger headers are the norm, although some have done the "shorty" short tube headers, with some difficulty. Some jsut do the cast iron manifolds, but generally a bolt in, and it's a good bit of weight too.

 

My Z has 1-5/8" PN 2100 Hooker block hugger headers, 2.5" mandrel bent duals, 2.5" X-pipe, and two 2.5" Dynomax Hemi Super Turbo mufflers in the "stock" location. See more info and pics HERE. It took me over 80 hours on my back making that system from mandrel J-bends and straight pipe. Probably several hundred times getting out from under the car. I had to use a modified 280Z front diff crossmember to get the system up tight to the car.

 

A labor of love. I absolutely LOVE the sound. It's a sound I am almost certain you can't get with a single system. Most of the unique character has to do with the X-pipe. Think "muffled NASCAR". It's not light, that's for sure.

 

A dual into single system is much lighter, simpler to make, and easier to get ground clearance with.

 

I'm just a glutton for punishment ;D.

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Guest Anonymous

Just to give him a idea of how long a 'GREAT' exhaust takes doing it under the car like you did Pete, would you hazard a guess how many hours you had into it? :D

 

Ahem, read the post Lone, 80 hours wow.... That explains why yours is so cool, I may have had 10 into mine and its no where near as cool or tucked in. Yours rocks...

 

Regards,

 

Lone

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Guest Anonymous

hypothetical situation, you have a v8 conversion on your hands, you just put in the engine and tranny with the block hugger headers from hooker. I take it a trip to the muffler shop is in order (on a trailer of course)?

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If you install according to JTR (jagsthatrun.com), then yes, just bolt on the Hooker PN2100 block hugger and you're good to go.

 

Just make sure you tell them to jog the head pipe around on the drivers side so you can pull the oil filter out. Easy to do, but it's an extra bend. And tell them you want it UP TIGHT TO THE BODY!

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I'm using Hooker's ceramic coated huggers and they work just fine. No shaving or milling needed at all. I first tried a set of Dynomax huggers and couldn't get the spark plugs in, even short ones.

 

Others have used long tube headers but there are various ground clearance issues. Ask Tim240Z about his issues with the SS headers and the T56 tranny.

 

Owen

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Questions:

1) How much more do the cast iron stock exhaust

manifolds weigh than headers?

2) Why did Chevy use cast iron on the Corvette

Z06 LS-6 enginer rather than headers?

Just trying to figure out why the OEMs always go with cast iron when the aftermarket seems to go for mandrel bent tubular steel headers.

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getting a little off topic twak.gif what about giong from dual 3" off the headers into a single 4" from the tail hsg back? what i'm really concerned with is groud clearance. right now in my camaro i have about 2 3/4" to 3" . it's not really a problem until i get a passenger. also does anyone no of a company that makes oval pipe. thanks 2thumbs.gif

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Just trying to figure out why the OEMs always go with cast iron when the aftermarket seems to go for mandrel bent tubular steel headers.

Phantom: Here's the answer:

 

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

 

Much cheaper to mass produce cast iron headers.

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Originally posted by Tim240Z:

quote:

Just trying to figure out why the OEMs always go with cast iron when the aftermarket seems to go for mandrel bent tubular steel headers.

Phantom: Here's the answer:

 

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

 

Much cheaper to mass produce cast iron headers.

Hrm, not 100% true. Ford used "stainless" on their 5.0 Mustangs and on some of the other V8 cars possibly. Cast iron doesn't radiate heat as much and that might also be a plus. Cost is probably THE biggest reason though...

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Guest Anonymous
Originally posted by biohzrd:

getting a little off topic twak.gif what about giong from dual 3" off the headers into a single 4" from the tail hsg back? what i'm really concerned with is groud clearance. right now in my camaro i have about 2 3/4" to 3" . it's not really a problem until i get a passenger. also does anyone no of a company that makes oval pipe. thanks 2thumbs.gif

Try http://www.spintechmufflers.com (I believe thats it, the company Spintech has oval pipe that will make clearance a bit better. Dual 3" might be a bit tough, mine is 3" single from the right header back and while I admit its not tucked as close as it could be, if you want the car dropped down at all you'll probably find driveways off main streets that have a high crown just past the sidewalk are going to give your car kittens getting over them. 4" is kinda big, unless your putting 24valve cummins in there IMHO... ;)

 

Regards,

 

Lone

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thanks for the link lone. as far as 4" being a little big i'm afraid thats what it's going to take. my motor is really going to have to beable to breathe if you know what i mean. ;) for right now it's going to be the 406 but the 377 is on the stand and i'm waiting on the to4's to get rebiult. then i'll most likely end up killing myself. may find a twin turbo z on ebay when that happens 2thumbs.gifrockon.gif and yes i may be a little bonk.gif

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Guest Anonymous

i thought naturally aspired engines had to have a certain amount of backpressure in order to function correctly. Wouldnt a 4" exhaust system on a SBC be a little too big? I had a 3" turbo back exhaust on my turbo eclipse a while back and i still think it was too big for the engine. What i would like to know is where you guys have the pipes exit on the car (i.e. sidepipes, dual tips out the back, etc) and also which diameter is most often used, or rather, what is a general diameter that i could use just to start off with?

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  • 1 month later...

Yeah I had problems with the S&S full length block hugger headers. I ended up making up a set of Tri-Ys, full length (1.75, into 2.25, into 3), then into dual 2.5" into single 3". Single Dynomax muffler in the back. Sounds pretty mellow, while not under any load. I may still weld in a crossover tube between the duals (at the collectors), and if still not happy, I will put in some bullet type mufflers in the duals, but at this point it sounds wonderful as is!

 

header pics

Header pics

 

Tim

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