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Headers / Dual exhaust????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Greg chezem, Jun 30, 2003.

  1. Greg chezem

    Greg chezem Registered Member

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    Need advice. Have a '90 k5, with a std350ciTBI and I'm looking to install 'true dual' exhaust. Would also like to install headers.
    so; two questions, first is what kind of headers do you guys recommend for a 1990 350motor (one I don't have to fudge anything like air sensors) and second, are there 'ready made' exhaust pipes that I can install or is this something that needs to be custom bent at a muffler shop?

    Please let me know. I'm trying to get as much hp out of this thing without losing gasmileage. also considering the edelbrock multiport injector at some point but that's another project for later.
    Thanks for your help
    Greg Chezem
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    The first, most obvious question, is how stringent are your emissions inspections/testing. (do they have them where you are?)

    If there are none, or they don't care about originality, on to your second part. There are not, that I am aware of, any complete true dual exhaust setups designed with headers, that will drop right into your truck. The gas (diesels did) K5 hasn't had "true duals" since the 70's, so finding a "bolt in" setup that is listed as fitting a '90 is going to be hard or impossible to come by, since that is technically illegal. (so is having a shop do this, so make sure you can find one that will)

    Check around on the board here (search), but talk has been of the Thorley tri-y's lately, also seen some about the Edelbrock TES.
     
  3. blasterD

    blasterD 1/2 ton status

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    I bought a pre-fab exaust kit from summit. It comes with Dynomax super turbos for around $100. It fit well. I'm not sure if they have an application for blazers, but I'm sure it wouldn't be very hard to modify a shortbox setup for your k5.
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I'll 2nd the dynomax kit. I have one on both trucks. Manifold duals on the C30 and Dynomax Jet-Hot coated headers and duals on the K10. Glasspacks on the C30, straight pipes on the K10. /forums/images/graemlins/smile.gif
     
  5. Greg chezem

    Greg chezem Registered Member

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    Though I'm in VA, we're in a county that is deemed 'agricultural' which is another way of saying 'anything goes' (and pretty much does). Not to say it will be this way for long if the burocrats have their way.
    The the second bit, I do have friend that is willing to run the pipe for me but has to do it afterhours so his boss doesn't know.
    Why is this illegal if I'm running quiet mufflers and Cats on both pipes?
    Greg
     
  6. Greg chezem

    Greg chezem Registered Member

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    BlasterD, do you know of a difference between the 'summit truck headers' and the Dynomax brand? (other than price)

    Heard of alot of guys going with the dynos so just wondering.
    Greg
     
  7. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    If you've got cats on both pipes and you have at least some kind of muffler then you are good to go. But most people that run true duals on here don't put cats on it, which is illegal (for 78 and later models), but won't stop me. /forums/images/graemlins/grin.gif So if you don't have emissions testing and you have freinds in high places that will weld it up for you, then don't put in cats. No sense in spending $200 for a pair of high flow cats when you can use that money towards a nice set of thorley headers.
     
  8. rick88blaze

    rick88blaze 1/2 ton status

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    i'm planning on going with the dynomax headers and prebent dual exhaust on my '88 K5. the headers are about $160 and the exhaust is about $112 both from jeg's, i believe summit carries them also.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Why is this illegal if I'm running quiet mufflers and Cats on both pipes?

    [/ QUOTE ]

    Because it is *federally* illegal to modify the number of converters the vehicle was originally equipped with. (+ or -) Stupid law, yes, but converters are somewhat finicky in temperature and what not, so they covered all bases and made sure there were no loopholes. (except that you can install a dual cat setup from, say, a Camaro, as long as the entire engine and all emissions from that vehicle are retained)

    Used to be illegal for shops to even change the converter, except under VERY specific conditions, but now it's not quite so bad. Of course, never heard of anyone getting nailed by the fed's, but ask your buddy why he has to do it without the boss knowing. /forums/images/graemlins/smile.gif I think the maximum fine is $10,000 for a shop OR private individual. Can't find anyone here that wil say yes, at least over the phone, and even ones I've talked to in person.

    That said, it can make the vehicle more difficult to sell later on if that may be in your plans. If you can't sell it in an emissions checked area, that may cut into your ability to sell it at all. I know around here it would make it much more difficult, unless I wanted to mislead the potential buyers, which I wouldn't (and didn't) do when I sold it.

    Not saying don't do it, just consider possible ramifications.
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I have yet to see proof of a law that makes bending an exhaust system for a smoggable car without cats is illegal. IIRC, it is illegal to remove the cat, but working on a car with the cat already removed seems to be a loop hole.

    Of course, laws can and do change often, but I've failed to ever see where someone posts from smog laws about it being illegal to work on a car without properly functioning emissions devices. Of course removing them is illegal, so go ahead and do it yourself. That removes the liability from the shop that works on your truck in the future.

    Of course I don't know this to be fact, that's just an observation I've made.
     
  11. blasterD

    blasterD 1/2 ton status

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    I'm not sure of any difference between the Summit and Dynomax headers. I run Hedmans and I am very happy with them. They seem to be of much higher quality and they are just as cheap. I got mine for arount $90 from Summit. They fit well and I have complete access to all plugs/filters.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    no you can't
    Number 6 pretty much answers you.

    Anyone that thinks there are any loopholes for converter equipped vehicles, read this.
     
  13. blasterD

    blasterD 1/2 ton status

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    Here are the Summit part #'s for my exaust.
    http://store.summitracing.com/partdetail.asp?part=WLK%2D89004&view=2047
    http://store.summitracing.com/partdetail.asp?part=WLK%2D17731 Needs 2 of these.
    http://store.summitracing.com/partdetail.asp?part=HED%2D69090
    They work really well. I like the sound, it sounds healthy, but not too offensively loud. I'd say about same volume as 50 series Flowmasters. It's pretty quiet at idle and gets progressively louder as you stomp the skinny pedal. Good deep mellow tone for much less $ than Flowmasters. Not that Flowmasters are bad, I just didn't have the money to spend on them at the time. I was suprised how well the pipes fit around the transfer case. The only problem I had was the shackle bolt on the passenger side. I installed it with the bolt pointing in and it rubbed just a little. It would be fine if the bolt were installed pointing out.
     
  14. jjlaughner

    jjlaughner 3/4 ton status

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    I'm planning on using the y-pipe to a 3" cat, 3" in / dual 2.5" out flowmaster and I'll have duals, use less pipe and only have to buy one coverter and muffler /forums/images/graemlins/thumb.gif /forums/images/graemlins/rotfl.gif
    I dont know, in idiana its not really a big deal, I know alot of people that just straight pipe 2000+ rides and unless the cops is a jerk and hunting for something to ticket you about there's not much of a problem and no emissions /forums/images/graemlins/thinking.gif
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    no you can't
    Number 6 pretty much answers you.

    Anyone that thinks there are any loopholes for converter equipped vehicles, read this.

    [/ QUOTE ]

    Read it again. It says as long as they don't work on the part of the system that the converters are supposed to be, the muffler shop may work on it. Looks like their is a loophole, as long as where the converter WAS, you put the test pipe. Then YOU have violated the clean air act, not the muffler shop.
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Read it again. It says as long as they don't work on the part of the system that the converters are supposed to be, the muffler shop may work on it.

    [/ QUOTE ]

    How do you get that out of:

    "If a converter-equipped vehicle is brought into a muffler shop with NO EXHAUST SYSTEM past the exhaust manifold or headers, is it tampering to install a non-stock or dual exhaust system? Answer: Yes."

    You can bet your bottom dollar that a shop even TOUCHING that system, with the intent NOT to replace the converter, is going to be viewed as committing a crime by the shop. Of course, if they were going to replace the converter, it would be a non-issue. However, what shop is going to risk $10,000 that they aren't being "tested" by an EPA employee? I'm sure thats why none of them will touch non-stock exhaust systems, at least in *most* locations.

    But aside from all that, it also covers the non-stock stuff. If it wasn't stock for that vehicle, or the newer engine installed in the vehicle, it's illegal. That's why you can't put duals on the later trucks legally.
     

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