Old valve cover thread

Discussion in 'VIN, Trim Tag & Drivetrain Decoding' started by Gary S, Jun 11, 2017.

  1. Gary S

    Gary S Administrator Lifetime Gold Member

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    Apr 14, 1999
    Bismarck, North Dakota
    I'm digging up this old valve cover thread because I have some pictures to add. This 2011 thread discussed the differences between the Z28/Corvette/LT1/L82 covers over the years.

    http://nastyz28.com/threads/1970-and-1974-z28-valve-covers.218974/

    The old thread indicates that the 1969 covers should be casting number 3932418. These covers had no drippers for the rocker arms. They were used on 1969 Z28 and Corvette L46 engines. I have no pictures of them. They have 3" cutouts of the rim for clearance to the intake.

    The 1970 covers have casting numbers 3965543LH and 3965544RH. They are exactly the same as the 1969 covers except for the numbers and the drippers were added for 1970. They also have the 3" cutouts. These covers were used on Z28 Camaro and Corvette with LT1 and L46.
    70coverclose.jpg 70coverwide.jpg

    The 1971-72 covers are the same as the 1970 covers except for another number change and the hole for a push in oil cap in place of the earlier twise in cap.
    I don't have a set of them to take pictures, but maybe someone with a set can contribute some pictures. These covers as far as I can find information would have casting numbers 3989005 & 3965542. Additional pictures would either confirm or prove me wrong. These covers would be the same as the 1970 covers except for numbers and push in cap hole. Again, the clearance cutouts are 3" on each side.
    Used on Z28 and Corvette LT1.

    1973-77 covers again were different. They carry the casting numbers of HL 3455693 & HR 4455693. This version went back to the twist in oil cap. The drippers are shorter than the earlier covers. The cutouts changed. My set has a 3.5" and a 5" cutout. I have read of others with slight variations on those sizes. These covers were made in both polished aluminum and black for the L82 Corvettes. These are also likely the versions sold over the parts counters at GM for many years.
    73close.jpg

    73coverwide.jpg
     
    70lt1z28 likes this.
  2. FlaJunkie

    FlaJunkie Veteran Member Lifetime Gold Member

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  3. jbloake

    jbloake Veteran Member

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    image.jpg image.jpg Another set SBC with cross flags Black , twist in cap,with drippers 3 1/2 "& 5" cut outs
    464669 ,464670
     
  4. Gary S

    Gary S Administrator Lifetime Gold Member

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    Bismarck, North Dakota
    jbloake,
    Do you have any idea of what year engine those covers are originally from? The cutouts seem to indicate that they are 1973 or later, but my 1973 covers have different numbers on them than yours do. I'm beginning to think that if enough covers are checked that we will find many different casting numbers for the years of 1973-77 and even later for the parts counter covers.
     
  5. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    Beavercreek, Ohio, USA
    Not wanting to hijack this thread, but does anyone know if you can run polylocks on the 70 covers with dippers? Don't really want to knock the dippers off. I do have access to a machine shop to do minor mods to the locks (grind the hex's down a bit?). Just wondering how close they are to fitting or is it totally a no-go. Don't really want to run thick gaskets or spacers either. Also, is there a consensus on the best no-leak gaskets for these?
    Thanks Gary for the photos.
     
  6. Gary S

    Gary S Administrator Lifetime Gold Member

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    Bismarck, North Dakota
    I made a quick measurement on one of my valve covers. There appears to be just under 1 3/4" space from the valve cover flange up to the bottom of the dripper. Adding a gasket should make it a full 1 3/4" or so. If you can measure one of your heads assembled with the polylocks, it might give you an idea of how close it gets to the cover.
     
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  7. jbloake

    jbloake Veteran Member

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    Unsure of original year these covers are . They had some black on them. I picked them up in parts deal. I think maybe Corvette 78-82
     
  8. Budz

    Budz Veteran Member Lifetime Gold Member

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    Ashburn, Va USA
    Mine hit the locks and I ended up having to double up stock cork gaskets. Been that way for years with no problems. The single thicker aftermarket gaskets my builder told me to use weren't thick enough. With the doubled gaskets, I couldn't use the 'correct' head-mark bolts if that matters to you, and had to use longer ones.
     
  9. zfool

    zfool Veteran Member

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    May 19, 2014
    Rochester, MN
    Here's the covers from a 29,000 mile 74Z with HEI Retainers 2nd week August build.
    3965543 LH
    9365544 RH
    [​IMG]
    [​IMG]
    [​IMG]
     
  10. 1970_Z28_503

    1970_Z28_503 Member

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    Apr 12, 2017
    Oregon
    off my 05D 70 Z28

    IMG_5626.JPG IMG_5627.JPG
     

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