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Are there good headers out there for an L31 Vortec?

This is a discussion on Are there good headers out there for an L31 Vortec? within the Exhaust forums, part of the Performance category; I will be replacing my 5.7 350 pretty soon and wanted to figure out if before I put it in ...

  1. #1
    Registered User FSUNole17's Avatar
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    Are there good headers out there for an L31 Vortec?


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    I will be replacing my 5.7 350 pretty soon and wanted to figure out if before I put it in if there are any good headers that show significant performance gains out there. Thanks

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    Registered User big burby's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    plenty of long tube headers show gains shortys suck no scavenging and only slightly improve flow for horsepower equal length runners for torque tri y are teh way to go
    315 on stock 2500 don't lift cut it off just get dented anyways:fsc:

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    Slow-N-Steady TigerEyz3's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    While I won't say shorties suck, they do not deliver the same increases as LTs or mid-length headers. Shorty headers are basically manifold replacements - but are not nearly as restrictive as the stock manifolds. One positive of shorties is that they do not require additional exhaust modification to install.

    LT headers deliver the greatest gains over stock. However, they are typically designed/tuned for a single RPM band rather than for daily driving/towing applications. Typically, they are not emissions legal and they also require more extensive exhaust modification - cats and O2 sensors have to be relocated oftentimes.

    Based on my research, I've learned that the best headers for the 5.7L trucks (that are used like a truck) are tri-y in design. They increase TQ/HP throughout the RPM band and though they do require some exhaust modification, the modifications are not extensive and can be done pretty easily - remove factory exhaust from manifolds to just before the cats; no sensor or cat relocation is necessary. That said, I've been very pleased with my Thorley headers.

    Regardless of your final decision in length, I would suggest spending the extra coin on ceramic coating - it help keep underhood temps down and will reduce corrosion (internally and externally).

    BTW, where in TN are you located?
    Prov 3:5-6; Jer 29:11
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    Re: Are there good headers out there for an L31 Vortec?

    I use my truck for daily driver/hard towing, looking for MORE Power and gas mileage. My manifolds are all rusted and pitted so thinking about new headers. But I am on kind of a budget too. The ceramic Thorleys on Summit are 700 bucks! Is that pricey? What are other brands that would be good qaulity but more in the <$500 range. thanks

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    Registered User FSUNole17's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    Quote Originally Posted by TigerEyz3
    While I won't say shorties suck, they do not deliver the same increases as LTs or mid-length headers. Shorty headers are basically manifold replacements - but are not nearly as restrictive as the stock manifolds. One positive of shorties is that they do not require additional exhaust modification to install.

    LT headers deliver the greatest gains over stock. However, they are typically designed/tuned for a single RPM band rather than for daily driving/towing applications. Typically, they are not emissions legal and they also require more extensive exhaust modification - cats and O2 sensors have to be relocated oftentimes.

    Based on my research, I've learned that the best headers for the 5.7L trucks (that are used like a truck) are tri-y in design. They increase TQ/HP throughout the RPM band and though they do require some exhaust modification, the modifications are not extensive and can be done pretty easily - remove factory exhaust from manifolds to just before the cats; no sensor or cat relocation is necessary. That said, I've been very pleased with my Thorley headers.

    Regardless of your final decision in length, I would suggest spending the extra coin on ceramic coating - it help keep underhood temps down and will reduce corrosion (internally and externally).

    BTW, where in TN are you located?
    Thanks for the in-depth analysis. I am in Fairview, TN, about an hour from Smyrna. Everyone talks about he Thorley, where do you see them on Summit?

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    Slow-N-Steady TigerEyz3's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    On the Summit Racing website, search for:
    DTE-302Y-FED-C (2wd)
    DTE-301Y-FED-C (4wd)
    Last edited by TigerEyz3; 09-06-2007 at 05:03 PM.
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    Re: Are there good headers out there for an L31 Vortec?

    other good brands maybe? They don't need to ceramic cause I can get that done at work.
    1996 C2500 5.7L reg cab/long bed 158000 miles and still rolling ex-county vehicle

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    Slow-N-Steady TigerEyz3's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    If you're interested in the non-coated Thorley's drop the "-C" and search again. Prices will be lower for sure.
    Prov 3:5-6; Jer 29:11
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    Re: Are there good headers out there for an L31 Vortec?

    Where's the cheapest place for Thorley's for a 5.7?
    1996 C2500 5.7L reg cab/long bed 158000 miles and still rolling ex-county vehicle

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    Slow-N-Steady TigerEyz3's Avatar
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    Re: Are there good headers out there for an L31 Vortec?

    When I was searching, the cheapest price was at Summit.
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