# '67 Quadrajet Base Gasket Configuration



## chemnick (Nov 16, 2013)

Hey Guys:
When I took the carb off of my engine some time ago, I never paid much attention because the carb only came off cleanly and everything else stayed put. Now I'm prepping my intake for blasting and I'm not sure what's there is correct. I have a '67 style gasket to the '67 intake, then the metal plate, then a standard type Quadrajet gasket on top (no cutout matching the exhaust crossover in the intake). I was at Ames last Thursday and asked the guy there about it and he said that the metal plate should go directly to the intake with the '67 type Quadrajet gasket between it and the carb only. The milling on the intake is clean but I'm not so sure it is going to seal against the very smooth surface of the metal plate. It almost seems like if there is supposed to be only one fiber gasket it would be better if it were under the metal plate instead. How is it supposed to go?
Thanks,
Chemnickconfused:confused


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## chuckha62 (Apr 5, 2010)

The heat crossover channel is a source of frustration on the '67s. I blocked mine with two plugs. I agree with you that the steel gasket placed directly on the manifold can result in a vacuum leak, so I use the fiber gasket, the metal gasket and another fiber gasket on mine. Make sure you put the two fiber gaskets on right side up (particularly the top one), or you will have a vacuum leak.


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## geeteeohguy (Feb 2, 2008)

I've been running mine like Chucka, but did not block the passage. Gasket on intake, steel plate, another gasket. Sandwich. The way I look at it, the extra gasket on the intake side acts as a heat insulator. Also, with the plate in place, plugs are kind of redundant. I'm ashamed to say I have run without this plate in the past and had vapor lock issues. It is necessary on the '67. My car also has a fuel vapor return line, which helps in hot weather. It gets up over 110 degrees where I live routinely during the summer, and it never misses a beat.


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## chemnick (Nov 16, 2013)

Thanks for the info, guys. The only issue I now have is if the top gasket to be used is the kind with the cutout matching the crossover in the intake. However, if the goal is to effectively block it off totally, two plain old Q-jet gaskets will do, or would that not match up to the shape of the intake surface? I do have a '68 intake as well which appears to be the same in all aspects, with the exception of the crossover. I'm trying to be careful of height, as I have acquired the components to make it RA and when I test fitted everything prior to sending the body for restoration, there was a little too much "up pressure" from the foam seal on the pan to the hood, but I figured the seal would "break in" and settle down a bit. I would have to check, but I would think the carb mount height would be the same. I kind of want to use the '67 manifold, as the car is a '67 and I've put in some time grinding the casting boogers off everywhere and opened up the intake ports to match the gasket profile.


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## geeteeohguy (Feb 2, 2008)

My whole sandwich deal is maybe 1/8" tall. That's 2 gaskets and a spacer plate. You _are _using a '67 carb on the '67 manifold, aren't you?


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## chuckha62 (Apr 5, 2010)

IIRC, The "regular old" Quadrajet gasket used on the '67 carb. will open that passage under the carb. to the atmosphere and create the vacuum leak. Oddly, after Pontiac tried and retired the design, Chevy picked it up and tried it in '69 for the 300HP 350 and had the same issues.


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## chemnick (Nov 16, 2013)

Yes, I sure am. When the project is done there will be new body mounts, new motor mounts, etc. so I'll be curious to see how things sit at that point. BTW, I do not know about another thing. The hood insert on the car has slots cut between all of the ribs in


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## chemnick (Nov 16, 2013)

(con't)..the back. Looks kind of cool, but I'm not sure it will allow enough air if I don't remove everything inside the scoop area. I'll post a pic in the future.
Chemnick


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## geeteeohguy (Feb 2, 2008)

I did that on my '67 many years ago. I have the fins, but I removed the backing with a cut off wheel. I cut the flap out of my hood, though, as I was running a ram air set up at the time. The main gain is cool outside air. There is basically no 'ram' effect at all.


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## steve491 (Nov 20, 2019)

I'm going to bring this thread back to life with a twist. Sorry if there's a newer one. I have a 67 with the exhaust crossover channel and a Holley spreadbore. It was installed with the proper gaskets and steel plate as stock and it worked fine. I have Trans-Dapt 1" spacer that I would like to install. It's a wide open spacer, not a four hole. Has anyone ever done this with a 67 manifold? From bottom to top I'll install a fiber gasket with four holes and the cutout for the channel, metal spacer plate, wide open spreadbore gasket, then carb. I believe this will work fine even though the bottom fiber gasket has some material in the middle that is not getting squished. Comments?


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## Roqetman (Aug 31, 2015)

Steve491, My opinion is to not use a wide open gasket/spacer at all. In order to get proper Venturi effect, each bore of the carb should match up with the intake opening, assuming your intake is a 4 hole spread-bore, dual plane intake. My question for you is where did you get a spread bore Holley, I thought they quit making those years ago? i’d be interested in knowing if they or anyone makes a new model sqreadbore carb. Thanks!


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## geeteeohguy (Feb 2, 2008)

steve491 said:


> I'm going to bring this thread back to life with a twist. Sorry if there's a newer one. I have a 67 with the exhaust crossover channel and a Holley spreadbore. It was installed with the proper gaskets and steel plate as stock and it worked fine. I have Trans-Dapt 1" spacer that I would like to install. It's a wide open spacer, not a four hole. Has anyone ever done this with a 67 manifold? From bottom to top I'll install a fiber gasket with four holes and the cutout for the channel, metal spacer plate, wide open spreadbore gasket, then carb. I believe this will work fine even though the bottom fiber gasket has some material in the middle that is not getting squished. Comments?


 You should be ok....but need to cut out the bottom gasket and steel plate as well to match the spacer. I guess you are doing it for heat soak reasons? Otherwise, on a stock type car, there are no gains to be had, and possible loss of low end torque. A lot of guys (not me) install pipe plugs into the two exhaust holes in the intake passage under the carb and run plain jane gaskets with no steel plate. As long as you have the steel section blocking the front passage, and the lower gasket opened up, you should be just fine.


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