Q-jet gasket question

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Mar 28, 2017 | 02:22 PM

sullyman56

Thread Starter

Drifting

Joined: Nov 2013

Posts: 1,546

Likes: 281

From: Scottsdale Arizona

Q-jet gasket question

This morning I laid the gasket on the manifold with the studs in the rear to
check for proper fit and I noticed that there's an area on the driver side near the front of where the carburetor sits that's open. This seems kind of odd since it's the correct GM aluminum manifold for my 69 427. Wouldn't this cause a huge vacuum leak and is there a resolution? Thanks in advance

Looks like I need a different gasket set. I should've read the paperwork from Lars with the Q-jet he rebuilt for me. Duh

Last edited by sullyman56; Mar 28, 2017 at 03:01 PM. Reason: .

Mar 28, 2017 | 03:55 PM

Surfer69

Drifting

Joined: Apr 2002

Posts: 1,720

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From: Manhattan Beach Ca

Looks to me like intake compatibility. What kind or number is your intake?

Last edited by Surfer69; Mar 28, 2017 at 03:55 PM.

Mar 28, 2017 | 03:58 PM

Alan 71

Team Owner

Joined: Sep 2006

Posts: 31,235

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From: Westminster Maryland

Hi s,
Would this be the correct one.
It encloses the heat passage.
It appears to be the second one that MW listed the link to.
Regards,
Alan

I think they're pretty readily available.
Lars' photo.

Last edited by Alan 71; Mar 28, 2017 at 04:18 PM.

Mar 28, 2017 | 04:14 PM

sullyman56

Thread Starter

Drifting

Joined: Nov 2013

Posts: 1,546

Likes: 281

From: Scottsdale Arizona

Quote:

Originally Posted by Alan 71

Hi s,
Would this be the correct one.
It encloses the heat passage.
Regards,
Alan

I think they're pretty readily available.
Lars' photo.

Yep, that's the one I just ordered along with the heat shield that goes on top. Thanks

Mar 28, 2017 | 04:21 PM

sullyman56

Thread Starter

Drifting

Joined: Nov 2013

Posts: 1,546

Likes: 281

From: Scottsdale Arizona

Quote:

Originally Posted by Surfer69

Looks to me like intake compatibility. What kind or number is your intake?

It's a GM aluminum intake for a 390 HP 427 for a Q-jet. GM part # 3947801. Just need the correct gasket.

Mar 28, 2017 | 05:09 PM

69Vett

Safety Car

Joined: Oct 2007

Posts: 3,729

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From: Austin Texas

Corvette of the Year Winner 2017

2016 C3 of Year Finalist

get the 1/4" thick oem version to avoid heat transfer to the carb.
and the related issues from boiling fuel.

Mar 28, 2017 | 07:47 PM

sullyman56

Thread Starter

Drifting

Joined: Nov 2013

Posts: 1,546

Likes: 281

From: Scottsdale Arizona

Quote:

Originally Posted by 69Vett

get the 1/4" thick oem version to avoid heat transfer to the carb.
and the related issues from boiling fuel.

Those I have plenty of. The other Corvette and my Chevy C10 both have Q-jets.

Mar 28, 2017 | 08:36 PM

68notray

Pro

Joined: Dec 2014

Posts: 699

Likes: 46

From: Charlotte NC

Many guys have ran into that on big blocks. GM did not use that gasket alone, there was a heat shield that went with it. The combination set is what seals the crossover passageway.

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Mar 28, 2017 | 09:23 PM

lars

Tech Contributor

Joined: Aug 1999

Posts: 14,377

Likes: 6,377

From: At my Bar drinking and wrenching in Lafayette Colorado

E-mail me for my paper about the Q-Jet Base Gaskets. It has part numbers and photos of the correct setup. You cannot use the gasket you have shown in your photo above. Info on this was included in the instruction sheet I sent you...

Lars
V8FastCars@msn.com

Last edited by lars; Mar 28, 2017 at 09:24 PM.