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Technical Corvette Valve covers

Discussion in 'Traditional Hot Rods' started by cheesegrater, Dec 29, 2013.

  1. cheesegrater
    Joined: Sep 1, 2011
    Posts: 114

    cheesegrater
    Member
    from california

    Ive got a pair of 9 fin Corvette valve covers were they unique to anything watching the B-J auction and have never seen a set even with a "100%" original fuelie & 2x4 ahy knowledge of them would be helpful for my curosity sake
     
  2. big duece
    Joined: Jul 28, 2008
    Posts: 6,152

    big duece
    Member
    from kansas

    The probably have the offset bolt pattern that was used up until '59. And they are ARE unique to Corvettes. Pretty rare.
     
  3. 3wLarry
    Joined: Mar 11, 2005
    Posts: 12,804

    3wLarry
    Member Emeritus
    from Owasso, Ok

    If I remember right, they came out in 1956 for the Corvette 2x4 and the Fuelie 265's. I think they were also used in early 1957 Corvettes and Bel Air's with the 283 with 2x4 and Fuelie motors.
     
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  4. olscrounger
    Joined: Feb 23, 2008
    Posts: 4,235

    olscrounger
    ALLIANCE MEMBER

    I think late 56 and 57 corvettes-dual quad or 57 Corvette fuelys--pass cars had tin valve covers on all engines--could be wrong my fuely BelAir has tin covers--always has
     

  5. brigrat
    Joined: Nov 9, 2007
    Posts: 5,374

    brigrat
    Member
    from Wa.St.

    I believe in '57 the FI air intake "drivers side" interfered with the top fin on the 9 fin so Chevy simply hogged the center of the fin for clearance.........
     
  6. redo32
    Joined: Jul 16, 2008
    Posts: 1,811

    redo32
    Member

    There are 3 different variations of 9 fin Corvette valve covers. Early '56 vette with 2x4 had covers without the relief cut on the inner gasket area for the intake manifold. Late '56 and 57 2x4 were relieved. The '57 fuel injected motor had the top fin machined for clearance for the air horn. '57 passenger cars used tin covers on the 2x4 motors, there are brackets to support the bat wing air cleaner.
     
  7. redo32
    Joined: Jul 16, 2008
    Posts: 1,811

    redo32
    Member

    I've wondered if the Vette valve covers were dealer installed options on pass cars. I've bored myself silly listening to so called experts debate the correct bracket for the air supply tube or the vacuum motor for the wipers.
     
  8. olscrounger
    Joined: Feb 23, 2008
    Posts: 4,235

    olscrounger
    ALLIANCE MEMBER

    redo32 nailed it--the ones for a 57 vette fuely are relieved for the FI air meter, Have never seen a pass car with vette covers orig but many folks installed them for better seal. My 57 Fuely has the vacuum wiper and electro vac pump
     
  9. devilleish
    Joined: Jan 15, 2007
    Posts: 254

    devilleish
    Member
    from Tampa, FL

    '56 and early '57 had the 9-fin covers, FI cars had the machined top fin, Chevrolet corrected it as quickly as possible with the much more common 7-fin covers.

    Delivered by a blind carrier pigeon.
     
  10. GM Performance lists a "original Corvette V-8 Valve Covers" under P/N 3726086. Offset bolt holes specified for 56-59 model years.

    At present GM does not show any inventory available for this part but does not indicate it as being discontinued at present.

    How close this is to the one being discussed I'm not sure as I do not have any in stock at this time to compare. Just thought I would mention it as I have sold a couple sets of these recently.
     
  11. longgoner
    Joined: Apr 15, 2007
    Posts: 84

    longgoner
    Member
    from western ny

    "Early '56 vette with 2x4 had covers without the relief cut on the inner gasket area for the intake manifold. Late '56 and 57 2x4 were relieved. "






    .... so does this mean the upper(inner) mounting flange is narrower on the late '56 and 57 but the p/n is the same ???
     
    Last edited: Dec 30, 2013
  12. redo32
    Joined: Jul 16, 2008
    Posts: 1,811

    redo32
    Member

    I don't have a set of early '56's, but I'm sure the flange was the same dimension all the way around. It also appears that all stagger bolt covers had the same part # despite the upgrades.
     
  13. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    These have the casting flaw running through the "o", the flaw didn't appear in the mold till around '67. They are also the 7 fin covers. Have no idea how much to O/P is concerned with "period correctness", just putting it out there for information.
     
  14. longgoner
    Joined: Apr 15, 2007
    Posts: 84

    longgoner
    Member
    from western ny

    Yeah, thanks redo32, now I think I understand .... the perimeter of the early version wasn't notched for the 2 intake plenums.
    May be wrong, but it seems there is also differences in the height of the corvette signature in the early years.
     
  15. redo32
    Joined: Jul 16, 2008
    Posts: 1,811

    redo32
    Member

    9 fin & early 7 fin Vette script was .030. Mid year '58 was raised to .125 tall letters.
     
  16. longgoner
    Joined: Apr 15, 2007
    Posts: 84

    longgoner
    Member
    from western ny

    Thanks for the history
     
  17. kyvetteman
    Joined: May 13, 2012
    Posts: 760

    kyvetteman
    Member

    The mold broke during the '66 production run and was repaired; hence the "casting flaw" seen in the late '66 and '67 factory installed valve covers. The decision was made to repair and not replace the mold as they were going to be phased out with the '68 model year anyway. They were still available from GM as recently as a few years ago, but were finally discontinued and no longer produced. Because of the long production run of the ones with the casting flaw, they are much easier to find than those without it. It's always been a pet-peeve of mine to see pre-66 vettes with covers that have the flaw when great pains have been taken to ensure accuracy otherwise.

    They still look cool as hell on hotrods, casting flaw or not.
     
  18. The 9 fins are a sought after (and pricy) accessory. You are lucky to have them.
     
  19. Mr48chev
    Joined: Dec 28, 2007
    Posts: 29,129

    Mr48chev
    ALLIANCE MEMBER

    Most likely not but the parts guy at the local Chevy dealership always had at least two or three pair of Finned Corvette valve covers on the shelf in the early 60's for around 30 bucks a pair if I remember right. I lost track of the number of them I helped guys install between 1962 and 1965. I never had a car that they would fit until after I was married and living in Texas though.
     
  20. olscrounger
    Joined: Feb 23, 2008
    Posts: 4,235

    olscrounger
    ALLIANCE MEMBER

    I'm with KYvetteman--covers after 66-67 have the casting flaw--earlier ones do not-have had many pairs of both .Still have a couple of pair without the flaw that I bought about 64 or 65.
     
  21. 54sled
    Joined: Feb 11, 2012
    Posts: 251

    54sled
    Member

    100% agreed,I love these covers on hotrods!
     
  22. Baumi
    Joined: Jan 28, 2003
    Posts: 2,745

    Baumi
    Member

    Great thread! I have a set of these on my 56 Chevy, but I never noticed a casting flaw. Where would I have to look for the flaw? Maybe anybody has a pic?
     
  23. 3wLarry
    Joined: Mar 11, 2005
    Posts: 12,804

    3wLarry
    Member Emeritus
    from Owasso, Ok

    flaw was through the O...but wasn't on early staggered valve covers.

    [​IMG]
     
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  24. DD COOPMAN
    Joined: Jul 25, 2009
    Posts: 1,121

    DD COOPMAN
    Member

    Here is a pic of the line runnung vertically through the "o" in Corvette...the "flaw". DD
     

    Attached Files:

  25. DD COOPMAN
    Joined: Jul 25, 2009
    Posts: 1,121

    DD COOPMAN
    Member

    Wha says 3wL is SLOW? DD
     
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  26. 3wLarry
    Joined: Mar 11, 2005
    Posts: 12,804

    3wLarry
    Member Emeritus
    from Owasso, Ok

  27. George Miller
    Joined: Dec 26, 2008
    Posts: 413

    George Miller
    Member
    from NC usa

    So that is what happened. My 66 vette that I have owned for 43 years does not have that flaw. Many people over the years said they should have a flaw. I always said they were original. I always said it is hard to believe they came from the factory with a flaw like that. But if it was near the end of the run it makes more sense.
     

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