Author Topic: 1969 Z/28 Camaro "472" Intake Manifold Expansion Plug  (Read 195 times)

Edgemontvillage

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1969 Z/28 Camaro "472" Intake Manifold Expansion Plug
« on: June 20, 2017, 06:34:45 PM »
The original, steel intake expansion plug from my 472 intake manifold was lost. I sent the intake to a well known restoration shop for re-skinning and was surprised to see the replacement plug they used was stamped with manufacturers' marks.  The original, factory installed 1 1/4" plugs had no marks so what I now have is incorrect. I have been trying to source a correct replacement steel plug and have ordered them from eBay sellers as well as HBC. Despite the item photos they all arrive with some form of manufacturers' stamping marks. I have even tried to grind out the stamp however the result is not suitable for a quality restoration. The original 302 from my Z/28 which is being rebuilt needed a set of replacement frost plugs which I was able to source from a Corvette restoration parts supplier with no manufacturers' stamping marks however I've been unable to locate a correct replacement intake expansion plug. Anyone have a confirmed source for unstamped, 1 1/4" steel intake expansion plugs?  

472 Intake with an incorrect replacement steel expansion plug showing stamped manufacturers' marks highlighted (source: eBay)



Typical frost / expansion plugs with stamped manufacturers' marks (source: Google images)




Lloyd
1969 RS Z/28 (Brooklyn Project)

Edgemontvillage

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Re: 1969 Z/28 Camaro "472" Intake Manifold Expansion Plug
« Reply #1 on: June 25, 2017, 03:11:24 PM »
Anyone?
Lloyd
1969 RS Z/28 (Brooklyn Project)

ZLP955

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Re: 1969 Z/28 Camaro "472" Intake Manifold Expansion Plug
« Reply #2 on: June 25, 2017, 03:36:03 PM »
Not aware of a source for an unstamped plug, but I'm sure a CNC machining company could run a few off for you if provided with one of the replacements to ensure dimensionally correct. May cost a little up front, but a limited batch could probably be sold to like-minded restorers to recoup some $.
Tim - 04A VN '69 z/28 69-69 715 ex-E/MP

68camaroz28

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Re: 1969 Z/28 Camaro "472" Intake Manifold Expansion Plug
« Reply #3 on: June 25, 2017, 05:12:48 PM »
Lloyd, don't know about manifold plug but for everyone's knowledge the "frost plugs" as you called them are still or were available from GM and still have the same look as originals with no other stampings.
Chick
68 Z/28 NOR 01B Orig motor/trans/rear
69 Z/28 NOR 07A Orig Block & GM Cross-ram/carbs
69 L34 Rest. Nova Father/Son Car
69 L78 Surv Nova Purch 4/69 31K miles
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R 68Z build- http://www.camaros.net/forums/showthread.php?t=182584

Edgemontvillage

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Re: 1969 Z/28 Camaro "472" Intake Manifold Expansion Plug
« Reply #4 on: June 26, 2017, 03:29:18 AM »
Lloyd, don't know about manifold plug but for everyone's knowledge the "frost plugs" as you called them are still or were available from GM and still have the same look as originals with no other stampings.

Chick, thanks, I've taken care of the frost plugs (casting plugs) however still trying to solve for the 1 1/4" intake manifold plug. Enio (Eddie) offered to machine a stamped plug to remove the stamping for me which sounds like a possible solution. I'd like to find an unstamped one.
Lloyd
1969 RS Z/28 (Brooklyn Project)