Original Finned Z28 Valve Covers

Discussion in 'Engine Topic' started by ratpatrol71z28, Apr 27, 2012.

  1. ratpatrol71z28

    ratpatrol71z28 Veteran Member

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    So yes I picked these Finned Aluminum Valve Cover LT1 Z28 for $100 pretty decent deal but would like to polish them up brightly to match my engine style... the previously owner painted them black but were not the LT1 Vettes covers I do believe... the set does have the metal twist on cap and insides have the dripper.... can someone tell me if these sound to be correct for my 71 Z ? Trying to put the engine back with originality...... I put paint stripper on and took off most the black and buffed a little piece.. shines beautifully but probably would like to professionally done? Any known prices ? Along with is the avaliabilty of the rubber gasket/gromets around to buy because mine are orginal and old? :)
     
  2. roeville

    roeville Veteran Member

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    71 Z should have a rubber plug.
     
  3. flowjoe

    flowjoe Moderator Staff Member Lifetime Gold Member

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    ^+1
     
  4. flowjoe

    flowjoe Moderator Staff Member Lifetime Gold Member

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    So you're kinda at odds here - to be correct-correct they need to have the press-in oil filler cap (as mentioned by roeville) and they would not be fully polished (OE is a smooth but dull finish). Later OTC, GM replacements came fully polished. The rubber grommets for PCV, etc are readily available from places like Classic Industries and others. GM may still even carry them.

    If you like polished and don't want to hunt for the push-in style then these will "pass" to the casual (read most) viewer. If you want technically correct then you need to go for what I have described.

    Good Luck
     
  5. Cardinal

    Cardinal Veteran Member Lifetime Gold Member

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    AND those valve covers won't shine up very well. They're (what appears to me) to be cast aluminum which has a lot of casting flaws in it. You'll probably wind up getting them chrome plated to get them to really shine.

    AND they have a problem with the oil wipers inside the covers hitting the rocker arms on high lift cam setups. Most people "fix" that by removing those wipers.
     
  6. ratpatrol71z28

    ratpatrol71z28 Veteran Member

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    Oh okay so what years did come with the ones I do have?
     
  7. COPO

    COPO Veteran Member Lifetime Gold Member

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    1969 302 Z/28 and 70 LT-1 came with the twist oil cap.

    [​IMG]
     
  8. Gary S

    Gary S Administrator Lifetime Gold Member

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    There were at least 4 slightly different versions.

    1. 1969- twist in cap like yours, but no drippers on the underside.
    2. 1970 & 1973-74-(yours) twist in cap and drippers
    3. 1971-72 push in rubber cap and drippers
    4. black painted with drippers from later L82 Corvette

    Both the #2 and #4 ones were also available for years at the Chevy parts counter until the supply ran out.
     
  9. flowjoe

    flowjoe Moderator Staff Member Lifetime Gold Member

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    They are cast and they polish just fine with small "marks" from casting. With a little more effort most of those can be sanded out and polished. Earlier valve covers seem to have fewer "flaws" than later ones (sloppy process or worn molds most likely).

    As noted by Gary the '69 variant has no oil drippers. These were added by GM to address rocker oiling (and I suppose GM must have had good reason to do so). They will not clear full roller rockers without a spacer but I have run roller tip and conventional rockers without issue. I currently run these covers (with drippers) on my '69 Z/29 with 302 and solid .493/.512 GM cam. I've never hit the drippers with the rockers so it must take a higher lift cam to do so.
     
  10. Z28PILOT

    Z28PILOT Veteran Member Lifetime Gold Member

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    One other notable diff . , their are alot of 79-81 ex-corvette black painted covers....these aren't the same material as the original early Alum covers either ( cheap pot metal )..buddy of mine just stripped a set and they are diff material magnesium or something he told me. So he had to find an actual early pair. I bought a late GM reissue pair , they suck , the material is wrong and they have no gasket wall to hold the gasket in place .

    The repro GM ones have a chrome gloss , that no matter how much you try the early 70's ones will not shine like those repops . SOme where in an old thread there were side by side pics of the Magnesium high polish vs the Originals ..totally different, and the dripper design is also different( ie. cheaper)
     

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