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Thorley Headers (who's got em?)

Discussion in 'The Garage' started by 78Suburban, Aug 17, 2005.

  1. 78Suburban

    78Suburban 1/2 ton status

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    I have some rusty old flowtechs, but honestly life is too short to worry with clearance issues and a leakey exhaust.... So I don't think I will put those on my 78 K20 burban with sbc, auto tranny on column.... I plan on a 4" lift soon

    After researching on this forum, the general consensus seems to be Dough Thorley... So I was wondering, will I run into ANY clearance issues with these headers? I have AC.... Would I have to change spark plugs from the stock AC Delco's, and would I have to change spark plug wires??
    Is the coating on these headers effective at keeping temperatures cool, and detering rust? What is the bet gasket to use to actually make it seal???? Any advise on these headers would be greatly appreciated......

    http://store.summitracing.com/defau...earchinresults=false&N=0&target=egnsearch.asp


    PS: anyone running prebent bolt on exhausts with these headers?? Do those clear any good?

    thanx ;)
     
  2. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    I've got the BBC ones on my K5 (304-Y)


    Pics of the fit (and frame notching req'd) are in my .sig gallery
     
  3. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    I didn't have any problem with clearance on mine. No A/C though.

    The standard finish is a nickel chrome, but I think they have ceramic for a lot more $$$. I don't think the chrome does much for heat, but they are not rusting up yet after about 6000 miles.

    I'm still using standard plugs. I have summit brand wires, and they are holding up okay and they were on the motor before the headers were.

    For the same money I would look at the Hedmen Elites if you are wanting something ceramic coated for heat. They have the same flange and tube thickness as the Thorleys.
     
  4. onlychevy6

    onlychevy6 1/2 ton status

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    i have them on my 88 c3500 big block. and they are great....
     
  5. k20

    k20 3/4 ton status

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    I had the nickel chrome on my 350, when I swapped up to my 454 I put on the ceramics. Fit is spot on, no clearance issues on either for me. Id go for the ceramics myself. Look better, even after mud baths, you can clean em, the nickel, once mud hits em, its there forever. Also the underhood heat is a little better.
     
  6. 78Suburban

    78Suburban 1/2 ton status

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    How much does Ceramic cost? What about header wrap, has anyone tried that? I would like to keep heat down, but my main concern is clearance....

    What gaskets are yall using?
     
  7. Smitty

    Smitty 1/2 ton status

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    The ceramic headers rust

    I have a set of their ceramic headers on my '56. They started to rust the day I put them on the truck :mad: . Put them on in Oklahoma so there wasn't any salt on the roads. They're good quality, expensive headers; just don't think they won't rust with a ceramic coating.
     
  8. 1-ton

    1-ton 1/2 ton status Premium Member

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    I have a set of thorley's on a 1985 K30 Dually with a 454, and They definitly cause clearance issues. They are very very close to the starter, and completly block the upper right hand front shock mount. The Thorley's also make it difficult to get at the flex plate cover and oil filter.
     
  9. 78Suburban

    78Suburban 1/2 ton status

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    I'm scared of clearance issues.... does anyone have them on a SBC K20 with AC??????

    Are stock manifolds and exhaust (with muffler cut off) just draining my engine's power to the bone???? are stock manifolds all that bad? What if I kept the manifolds and ran duals? I'm just wondering if I would really get much hp for the buck with headers?
     
  10. wy4tt

    wy4tt 1/2 ton status

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    I've got them on my '79 Jimmy with SBC. Just got them on, and they fit well. However, it does make getting to plugs a little tough. I still use the AC Delco plugs and wires that came with this crate motor (350HO). I have AC on mine, but I haven't gotten the brackets for mounting it yet. The compressor is on, and everything seems like it will fit ok. Overall, I like them a lot!
     
  11. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    Changing plugs is a bit of a chore but they helped alot on take-off and mileage went up a bit. Sounds lovely through 12 inch glass packs run out behind the rear tires! Ain't hooked up the A/C yet though.

    [​IMG]

    [​IMG]
    SS flex, no rust yet!
     
  12. k20

    k20 3/4 ton status

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    Wraps void thorleys warranty IIRC, I didnt have any issues on my 87 sbc k20 as I recall. The instructions do however have you cut a leg off of one of the brackets. Here is a pic from my webshots. If you look at the #1 tube, you can see where the leg was cut off. The instructions for doing so are included with the header. http://community.webshots.com/photo/44462346/37371404TuPStU That is the nickel chrome coating, before mudbaths, which left them lookin rusted and nasty, though they werent rusted. The ceramics on my bbc still look good.

    As for gaskets, I ran the ones supplied with the headers on my sbc, but I didnt run it very long before it blew up :doah: . On my BBC I am running a set of copper gaskets on the primarys as well as the collectors. No leaks.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    I think wrap voids pretty much everyones warranty, I know it was mentioned with my Hedman Elites.
     
  14. Desert Rat

    Desert Rat Fetch the comfy chair

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    I've got a 76 Blazer with no cat. Anybody have the same with Thorleys? I'm thinking I need a THY-364Y1 or maybe the THY-364Y8 which is listed for a 4-6 inch lift. What is the difference? Do they drop them down farther? ( http://www.dougthorleyheaders.com/gm_headers.html ) ?
     
  15. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    i came to the conclusion that the difference was a different y-pipe for the 4" to 6".... just a guess tho...
     
  16. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    E-mail or call 'em. I'm sure they'd be glad to answer ya. :laugh:
     
  17. Desert Rat

    Desert Rat Fetch the comfy chair

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    Sent them an e-mail. Where is the best place to buy Thorleys? Summit? 4WP?
     
  18. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    I have them on my '73 K5, with no clearance issues whatsoever. I can't get all the sparkplugs with a socket wrenck, I have to use a box end on a couple, but I like them, and after 25,000 miles, there is no rust. I bought mine from summitt.
     
  19. Desert Rat

    Desert Rat Fetch the comfy chair

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    Can you shoot a few pics? Do you have any problems with the spark plug wires touching the headers? What model number did you get?
     
  20. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Here's some photos. I have no probs with the plug wires hitting, you can see how I bundled them in the photos. I think thee model was the thy-364Y, but mine did not come with a y-pipe. It is not available for the '73 K5, I don't know why.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     

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