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Technical adapting early Olds valve covers to late 371 and 394 heads

Discussion in 'The Hokey Ass Message Board' started by Paul, Feb 10, 2024.

  1. Paul
    Joined: Aug 29, 2002
    Posts: 16,406

    Paul
    Editor

    I've been ideating with @Flatrod17 about adapting the '49-'58 two bolt covers to fit the '59-'64 five bolt heads.
    the biggest hurdle is that there is no provision in the later heads to place the early valve cover bolts.
    no bolt hole and no pad to drill and tap a hole.

    these two solutions work well with the first version '57 valve covers.
    I need to verify with 303 and 324 valve covers,
    the early (all?) 303 valve covers are about 1/4" shorter in length and may be an issue..

    edit:
    issue being: if the rocker assemblies include the towers at the ends of rocker shafts there will likely be interference with the 303 and 324 covers.
    if they do not have the end towers, I would expect all two bolt covers would work

    first attempt:
    trying to keep this simple as possible I cut a tab from some heavy gauge sheet metal, drilled two holes in it and welded a trimmed down nut to it.
    this would go under the head of the adjacent stock head bolt.
    It worked but still a little labor intensive.

    PXL_20240210_011029768.jpg PXL_20240210_011039192.jpg PXL_20240210_011046655.jpg PXL_20240210_011130182.jpg

    then Dennis suggested using the accessory head bolts, the ones that generators and power steering pumps use.
    so I made another tab, this time of 1/4" plate with a drilled and tapped hole for the valve cover bolt.
    still a bit of work involved and the special stud type head bolts would need to be sourced but no welding needed.
    I think this is a winner

    PXL_20240210_195909662.jpg PXL_20240210_201849262.jpg PXL_20240210_202159813.jpg PXL_20240210_202222482.jpg
     
    Last edited: Feb 10, 2024
  2. 42merc
    Joined: Dec 19, 2010
    Posts: 896

    42merc
    Member

    I like it. Good thinking.
     
  3. Tim
    Joined: Mar 2, 2001
    Posts: 17,176

    Tim
    Member
    from KCMO

    Holy cow that’s a game changer for the 394!
    Way more options with that.
     
  4. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,658

    Johnny Gee
    Member
    from Downey, Ca


  5. BJR
    Joined: Mar 11, 2005
    Posts: 9,876

    BJR
    Member

    So the gasket sealing area on the heads is the same from the 1949 303's to the 394's?
     
  6. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,872

    jimmy six
    ALLIANCE MEMBER

    I’d put a set of YBlock Fords, or Mel’s …..nothing like screwing up the masses.
     
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  7. Paul
    Joined: Aug 29, 2002
    Posts: 16,406

    Paul
    Editor

    303 valve covers are 1/4" shorter length wise than the 394 but should still seal.
     
  8. Moriarity
    Joined: Apr 11, 2001
    Posts: 31,011

    Moriarity
    SUPER MODERATOR
    Staff Member

    I put Olds Moon valve covers on the Cadillac engine in my Outlaw clone, because that is what Roth did. I realized that after I ruined a pair of Moon Caddy covers trying to make them look like Olds units. The Olds covers even seal on a Caddy but just barely
     
  9. Paul
    Joined: Aug 29, 2002
    Posts: 16,406

    Paul
    Editor

    ouch! that hurts!
     
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  10. Moriarity
    Joined: Apr 11, 2001
    Posts: 31,011

    Moriarity
    SUPER MODERATOR
    Staff Member

    Wasn’t a big deal at the time 2002, caddy valve covers were still available at moon and only about 200 bucks or so. Now though I think they are discontinued for a while already and guys are asking over a grand for em... oh well
     
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  11. bchctybob
    Joined: Sep 18, 2011
    Posts: 5,199

    bchctybob
    Member

    Clever solution. Adds valve cover options
    When you chrome them, those smooth 394 covers with perimeter bolts just say Big Powerful Olds to me. SWC, Hugh Tucker, McEwen & Adams. many other top Olds powered champions had ‘em. They look especially mean alongside of a natural finish 6-71. I’m still hoping to put a 394 in something someday.
     
    Paul likes this.
  12. Paul
    Joined: Aug 29, 2002
    Posts: 16,406

    Paul
    Editor

    I think the best looking of the stock stamped steel five bolt covers are the smooth ones.
    I have a couple pair painted and one pair old chrome

    PXL_20240211_011701598.jpg
     
  13. bchctybob
    Joined: Sep 18, 2011
    Posts: 5,199

    bchctybob
    Member

    I was exposed to this when I was a kid, never got over it….
    IMG_1575.jpeg
     
  14. Flatrod17
    Joined: Apr 25, 2017
    Posts: 467

    Flatrod17
    Member

    I didn't care for the stock 394 covers so I asked Paul about early to late. I like the early and now I know they will work so I just have to find some early ones.
    I do have plenty of different Y block covers, but I just don't think that would be right!
     
    Last edited: Feb 11, 2024
    bchctybob and Paul like this.
  15. I did the opposite, put a pair of Hildebrandt Caddy valve covers on a 371 Olds. Just had to put a little zig zag on the studs to line them up. They worked fine.
     
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  16. threewindaguy
    Joined: Jun 9, 2007
    Posts: 291

    threewindaguy
    Member

    i put finned t bird valve covers on a nailhead. talk about confusing people
     
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  17. Moriarity
    Joined: Apr 11, 2001
    Posts: 31,011

    Moriarity
    SUPER MODERATOR
    Staff Member

    as far as I know the only aftermarket valve covers for the Caddy engines were for engines with 4 perimeter bolt attachment. The 49 cad with 2 center studs were only produced for a couple of months and I was under the impression that there were no aftermarket covers made for them???
     
  18. These are what I have. Bought them back in the 80's. They never fit quite right. Had to offset the studs to line up with the bolt holes. Was told they were Cadillac. Top corners are more "square" than Olds
    IMG_1602.JPG
     
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  19. Moriarity
    Joined: Apr 11, 2001
    Posts: 31,011

    Moriarity
    SUPER MODERATOR
    Staff Member

    according to this old thread what you have are poorly made Olds valve covers. I think that you posted on pg 2 of that thread. It was stated there that the caddy with ctr bolt covers have a bolt spacing of 14 inches
    https://www.jalopyjournal.com/forum...-hildebrandt-center-bolt-valve-covers.874938/
     
    bchctybob likes this.
  20. 37slantback
    Joined: May 31, 2010
    Posts: 481

    37slantback
    ALLIANCE MEMBER

    I never liked my Offy covers.
    IMG_20210202_073557028~2.jpg
     
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