'66-'72 Holley 1x4 Air Cleaner Stud Photo

[Mike B.]

Happy Holidays Guys,

I've scoured the archives for this one but those photos are no longer retrievable. I'm especially interested in what an original Holley 1X4 carb air cleaner stud should look like for '65-'67 396/427 engines. Bubba tossed my '66 427/390hp's years ago. Pretty sure that '66-'67 small blocks had the same stud? Sure would appreciate a photo of a real one. The repros sold are said to be clones of later service replacements?

Thanks and Happy New Year,
Mike

[David B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

According to '66 P & A Grp. 3.403 396, 427 carb stud PN 3873852 is all by itself. 1/4-20-20 x 1 1/2

[Vernon S.]

[Vernon S.]

[Jack M.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Mike- Here are a few images to possibly consider... with increasing resolution:

1) From an October 1965 L72 magazine photo shoot (dealer stock vehicle):
1966-Corvette-(10-1965).jpg


2) From a Winter 2005 Restorer article by Everett Ogilvie... his original L72 carb (September 1965 build):
1966-Corvette-(09-1965)a.jpg


3) Zoomed into Everett's the air cleaner stud (left)... you can count the exposed threads, and observe the tip:
1966-Corvette-(09-1965)b.jpg

[Stephen L.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

This is my 67 3811 carb air cleaner stud....

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

According to '66 P & A Grp. 3.403 396, 427 carb stud PN 3873852 is all by itself. 1/4-20-20 x 1 1/2

Thanks David for looking this part up in your '66 P&A. I mistakenly left my copy up north. The 1 1/2" (inch and a half) dimension jives with what my friends have told me of what they feel are original studs to their cars. Photos coming...

I just ran a parts query of Stud#3873852 through Don Olson's AIM database for all midyears and here's what came up:

1965 UPC L78 / Sheet C3
1966 UPC 6 / Sheet C3
1966 UPC L72 / Sheet C3
1967 UPC 6 / Sheet C3
1967 UPC L36 / Sheet A-9

Thanks for your help,
Mike

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Hi Skip,

Always a pleasure. I was hoping you'd respond to this thread. You're probably the one person I know who's owned his '66 the longest. And you've had that beautiful L36 AC coupe almost since day one! I trust the originality of the parts you've shown us all in the past. Thank you very much for removing your car's stud so I'll know what to hunt for at swap meets! I'll share your email and photo here now. Take care, Mike

Skip Steinman's '66 L36 Original Stud Email.jpgSkip Steinman's '66 L36 Original Stud (2).jpg

[Joe L.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Thanks David for looking this part up in your '66 P&A. I mistakenly left my copy up north. The 1 1/2" (inch and a half) dimension jives with what my friends have told me of what they feel are original studs to their cars. Photos coming...

I just ran a parts query of Stud#3873852 through Don Olson's AIM database for all midyears and here's what came up:

1965 UPC L78 / Sheet C3
1966 UPC 6 / Sheet C3
1966 UPC L72 / Sheet C3
1967 UPC 6 / Sheet C3
1967 UPC L36 / Sheet A-9

Thanks for your help,
Mike

Mike------


The GM #3873852 stud was discontinued in June, 1976 and replaced by GM #3785256. The latter is the "one-size-fits-all" stud which is about 6 inches long and is shortened on both/either ends as required.

There are both good and not-so-good reproductions of the 3873852 available. However, all I've seen are zinc plated rather than black phosphate.

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Mike- Here are a few images to possibly consider... with increasing resolution:

1) From an October 1965 L72 magazine photo shoot (dealer stock vehicle):
[ATTACH=CONFIG]115029[/ATTACH]


2) From a Winter 2005 Restorer article by Everett Ogilvie... his original L72 carb (September 1965 build):
[ATTACH=CONFIG]115030[/ATTACH]


3) Zoomed into Everett's the air cleaner stud (left)... you can count the exposed threads, and observe the tip:
[ATTACH=CONFIG]115031[/ATTACH]

Hello Jack,

I was gonna get out Noland's book with my magnifying glass but you've beaten me to it with even better photos here. Amazingly a friend and I were just discussing looking up Everett Ogilvie's article for a good comparison as I drove home a while ago. And "voila" there ya go.

Sure looks like Everett's September '65 built car's stud jives with Skip's November '65 built one. I'll find a real one for my December '65 built L36 for sure. The repros look very close to Skip's but I always prefer the real deal.

Stephen, your 1967's stud sure jives with Skip's and these black & white photos. The thread count sure looks to be about 10 to me.
Thanks, Mike

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Mike------


The GM #3873852 stud was discontinued in June, 1976 and replaced by GM #3785256. The latter is the "one-size-fits-all" stud which is about 6 inches long and is shortened on both/either ends as required.

There are both good and not-so-good reproductions of the 3873852 available. However, all I've seen are zinc plated rather than black phosphate.

Good Afternoon Joe,

Thank you for responding. I always learn a lot from your posts. A few years ago I was very fortunate to find and buy a set of GM Engineering Standards books. I enjoy looking up the correct dimensions, strength and plating of the bolts, etc. listed in the midyear AIMs. But there's something that I've always been a bit frustrated over. Could you please tell me (and all) why there is no listed information for AIM part numbers beginning with "3" in these engineering volumes? For instance this stud #3873852. Is it because these parts were outsourced and not produced by GM?

If anyone would know it would be you. It would be great to know the original specifications of this stud. Thanks Joe,
Mike

[Joe L.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Good Afternoon Joe,

Thank you for responding. I always learn a lot from your posts. A few years ago I was very fortunate to find and buy a set of GM Engineering Standards books. I enjoy looking up the correct dimensions, strength and plating of the bolts, etc. listed in the midyear AIMs. But there's something that I've always been a bit frustrated over. Could you please tell me (and all) why there is no listed information for AIM part numbers beginning with "3" in these engineering volumes? For instance this stud #3873852. Is it because these parts were outsourced and not produced by GM?

If anyone would know it would be you. It would be great to know the specifications of this stud. Thanks Joe,
Mike

Mike------


7 digit part numbers beginning with "3" are GM car/truck division part numbers, usually Chevrolet or Cadillac. These are parts which the division designed and released and are not "Standard Parts" shown in the Engineering Standards reference. However, some of them may be carried in the "Standard Parts" catalogs (P&A 89A). The "Standard Parts" from the Engineering Standards are generally all carried under parts groups 8.9xx.

There are also some 6 digit part numbers beginning with "3" and "4" which were released in the 1973-79 time frame which are Chevrolet Division part numbers.

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Thanks Joe,

I knew you'd know. Maybe I can find these books for my library. I'll copy and file these references.

Mike

[E S.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Hi- This is 66 L72 #3795 (Oct 65)
E.J.IMG_20221228_162830962.jpg

[Mike B.]

Re: '66-'72 Holley 1x4 Air Cleaner Stud Photo

Thanks E.J.

Excellent shot!

And thanks to everyone who contributed photos and dimensions to this thread. I definitely know what to hunt for now. Mike