Carb Gasket - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Bullzak_83 · 09-09-2021, 10:09 PM

In the process of getting my 70 cst going for my sone, we are at the point of starting the engine. After setting up in the garage for 20+ years. We pulled the carb to go through it clean it up get the old gas out etc. When I pulled the carb off of the intake I noticed the gasket and riser plate did not seem right. Been a few years for me, since I have tore into a SB. But does this gasket and plate look right setting on the intake. I am running a Carter 4bbl.

Willys_MB · 09-09-2021, 11:06 PM

It’s hard to tell, but it might be an adapter plate to go from the stock spread bore intake to a square bore. Is the intake oem?

Bullzak_83 · 09-09-2021, 11:12 PM

Yes it is the intake is original, as far as I can remember

**tdangle** · 09-09-2021, 11:18 PM

Looks like you have a square bore Edelbrock carb on a spread bore intake manifold. I would ditch the idea of running an adapter and just pick up a decent square bore intake manifold. It will work best and have the best performance. Couple hundred and a few hours of work.

Willys_MB · 09-09-2021, 11:51 PM

Quote:

Originally Posted by tdangle

Looks like you have a square bore Edelbrock carb on a spread bore intake manifold. I would ditch the idea of running an adapter and just pick up a decent square bore intake manifold. It will work best and have the best performance. Couple hundred and a few hours of work.

Yup, this is exactly what I did this past winter. Definitely worth the effort

**Richard** · 09-10-2021, 02:42 AM

If motor is mostly stock I would ditch the Carter square bore and source a quadrajet myself.

**BigBird05** · 09-10-2021, 08:15 AM

If you don't want to buy anything right now and that type of gasket is sealing at the carb and at the intake I would just trim the portion of the gasket that is covering the ports on the intake. That would get you better flow into the engine. The carb and intake are miss matched, but if it ran before and you were happy with it you can leave that set up as is.

sick472 · 09-10-2021, 08:45 AM

If your carb is a square bore...they have adaptors that will transition the carb to the spread-bore intake. They are affordable and found in most AZ, O'Rielly's, etc. I have one in my truck that has an OEM spread-bore intake and a square bore Edelbrock. They do add about 3/4" to 1" rise in the carb which may effect air cleaner clearance and any hoses that would attach to it.

Changing the carb or the intake would probably be the best thing to do, but the adaptor route will be the cheapest and will be fully functional for a mild built motor. It may even add some slight performance by insulating the carb a bit more from the motor heat. This slight improvement is over just cutting up a gasket to make it quick an easy.

Tip: My adaptor came with a threaded port in the back for the vacuum line to the brake booster...that will need to be drilled out before it will work. But, my carb had that fitting too, so I just used the one on the carb and left the adaptor undrilled.

Bullzak_83 · 09-13-2021, 09:01 PM

Quote:

Originally Posted by sick472

If your carb is a square bore...they have adaptors that will transition the carb to the spread-bore intake. They are affordable and found in most AZ, O'Rielly's, etc. I have one in my truck that has an OEM spread-bore intake and a square bore Edelbrock. They do add about 3/4" to 1" rise in the carb which may effect air cleaner clearance and any hoses that would attach to it.

Changing the carb or the intake would probably be the best thing to do, but the adaptor route will be the cheapest and will be fully functional for a mild built motor. It may even add some slight performance by insulating the carb a bit more from the motor heat. This slight improvement is over just cutting up a gasket to make it quick an easy.

Tip: My adaptor came with a threaded port in the back for the vacuum line to the brake booster...that will need to be drilled out before it will work. But, my carb had that fitting too, so I just used the one on the carb and left the adaptor undrilled.

Hey Sick 472,
That's where Im confused I have a Summit racing mega store 15 mins from the house. And I have been told that what I have is normal and I have been told what I have is not normal. Problem is the truck has been sitting in my garage for 20+ years and honestly I don't remember how it ran. Just so happens my son works at a Auto Zone and I have him checking on this adapter

geezer#99 · 09-13-2021, 09:26 PM

You need an adaptor like this. They work either way. Just flip it over.

https://www.performance-world.com/Ca...ter-p/2066.htm

Tell your son to search for mr. gasket or transdapt name.

By the way the dark areas on your spacer indicate the carb was running rich or flooding a bit.

Bullzak_83 · 09-13-2021, 09:30 PM

Since I'm totally confused on what I have here are some pics. I have more if anyone needs them. Again I don't know if I have a spread bore or a square bore?

**Steeveedee** · 09-13-2021, 09:59 PM

That's technically a "square bore". Take a look at a Q-Jet or Thermo-Quad. They are technically spread bores. Even some old Carter AFB carburetors had larger secondaries. It gets confusing when people lay a label on a lot of stuff, and this carb is a case in point. It could go either way, but I'd call it square bore, personally.

**Grumpy old man** · 09-13-2021, 10:12 PM

Buy a Quadra jet and be done with it .

Bullzak_83 · 09-13-2021, 10:17 PM

Thanks for the info, I think i found one on Jegs.

Bullzak_83 · 09-13-2021, 10:21 PM

Quote:

Originally Posted by Steeveedee

That's technically a "square bore". Take a look at a Q-Jet or Thermo-Quad. They are technically spread bores. Even some old Carter AFB carburetors had larger secondaries. It gets confusing when people lay a label on a lot of stuff, and this carb is a case in point. It could go either way, but I'd call it square bore, personally.

Hey Steeveedee, That's where I'm confused, cause when I ask the guy at Summit he said it was a square bore because of the bolt pattern, but when I returned the adapter he had sold me, the next guy said no its a spread bore. And what I had would work.

**Grumpy old man** · 09-13-2021, 10:25 PM

Nothing sounds like a Quadra jet ,

https://www.youtube.com/watch?v=21NRsuVPrqQ

https://www.youtube.com/watch?v=88c-3NYMsvI

**Steeveedee** · 09-13-2021, 10:36 PM

Quote:

Originally Posted by Bullzak_83

Hey Steeveedee, That's where I'm confused, cause when I ask the guy at Summit he said it was a square bore because of the bolt pattern, but when I returned the adapter he had sold me, the next guy said no its a spread bore. And what I had would work.

I guess it depends on whether you have the adapter right side up or upside down. The videos GoM posted are of a Q-Jet (obviously) and that is a spread bore. If the guy told you that the adapter that fit the carburetor baseplate you posted is a spread bore, he is misinformed.

**Steeveedee** · 09-13-2021, 10:43 PM

Quote:

Originally Posted by Grumpy old man

Nothing sounds like a Quadra jet ,

https://www.youtube.com/watch?v=21NRsuVPrqQ

https://www.youtube.com/watch?v=88c-3NYMsvI

They sound WAY better under load.

https://www.youtube.com/watch?v=3666SqW9Xi0

geezer#99 · 09-13-2021, 11:55 PM

Here’s two gaskets side by each to compare spreadbore to squarebore.

https://www.speedwaymotors.com/Edelb...SABEgL-avD_BwE

Bullzak_83 · 09-19-2021, 08:39 PM

[COLOR="Red"]Hey, I want to thank everyone for the feedback and input.
geezer#99 and everyone else who recommended the carb adapter, found one tried it and it work like a champ.
After rebuilding my first carburetor, and a little valve adjustment the ole Chevy fired up today, and ran like a champ. Man I gotta say what a good feeling to hear that old truck after 20+ years sitting ion the garage.
Thanks again for the feedback..... [/COLOR]

burnin oil · 09-20-2021, 10:27 PM

Do you have any stumbles under heavy throttle from idle? I just pulled an adapter like that off of a project truck that had a holley on it. The adapter was about 1/2" thick and made some wicked flow issues. The holley worked flawless but the motor didn't run well. I pulled a qjet out of atleast a 5 year storage and installed it. The motor came alive instantly and power and driveability was way up. Even sounds like a different motor. This thing should have liked the holley better but the adapter and intake killed it. Just a thing to look out for. The front barrels where about 1/3 obstructed by the adapter. I bought the truck this way incase anyone questions my sanity. Good luck.

Bullzak_83 · 09-21-2021, 09:56 PM

Hey burnin oil.
I have not, BUT I have only just got the engine running last weekend. It has been in my garage for 20+ years. And we are in the process of getting set up for son, he wants a project truck, he now has one.

geunther · 09-21-2021, 10:47 PM

Quote:

Originally Posted by Grumpy old man

Nothing sounds like a Quadra jet

Back in my trooper days, we'd turn over the air cleaner to get that sound on the dispatch tape. Dispatch would get so mad because it was so loud. Motor pool would turn em back correct, we'd turn em over again.This went on for years

Loved to run 130 with that sound.

Apologies for the side convo on the Qjet sound.

burnin oil · 09-21-2021, 10:56 PM

And I am still flipping them to this day.

geezer#99 · 09-21-2021, 11:16 PM

You want a real howl, try running 2 quadrajets on a dual quad intake.

09-09-2021, 10:09 PM	#1
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Carb Gasket In the process of getting my 70 cst going for my sone, we are at the point of starting the engine. After setting up in the garage for 20+ years. We pulled the carb to go through it clean it up get the old gas out etc. When I pulled the carb off of the intake I noticed the gasket and riser plate did not seem right. Been a few years for me, since I have tore into a SB. But does this gasket and plate look right setting on the intake. I am running a Carter 4bbl. Attached Images

09-09-2021, 11:06 PM	#2
Willys_MB Registered User Join Date: Apr 2017 Location: Boise, ID Posts: 856	Re: Carb Gasket It’s hard to tell, but it might be an adapter plate to go from the stock spread bore intake to a square bore. Is the intake oem? __________________ 1968 GMC C2500 Long Bed Fleetside

09-09-2021, 11:12 PM	#3
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Re: Carb Gasket Yes it is the intake is original, as far as I can remember

09-09-2021, 11:18 PM	#4
tdangle Senior Member Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,209	Re: Carb Gasket Looks like you have a square bore Edelbrock carb on a spread bore intake manifold. I would ditch the idea of running an adapter and just pick up a decent square bore intake manifold. It will work best and have the best performance. Couple hundred and a few hours of work. __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC

09-10-2021, 02:42 AM	#6
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,693	Re: Carb Gasket If motor is mostly stock I would ditch the Carter square bore and source a quadrajet myself. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

09-10-2021, 08:15 AM	#7
BigBird05 Senior Member Join Date: Aug 2019 Location: Cheraw Posts: 1,305	Re: Carb Gasket If you don't want to buy anything right now and that type of gasket is sealing at the carb and at the intake I would just trim the portion of the gasket that is covering the ports on the intake. That would get you better flow into the engine. The carb and intake are miss matched, but if it ran before and you were happy with it you can leave that set up as is.

09-10-2021, 08:45 AM	#8
sick472 Registered User Join Date: Jul 2015 Location: Sedalia Mo. Posts: 1,130	Re: Carb Gasket If your carb is a square bore...they have adaptors that will transition the carb to the spread-bore intake. They are affordable and found in most AZ, O'Rielly's, etc. I have one in my truck that has an OEM spread-bore intake and a square bore Edelbrock. They do add about 3/4" to 1" rise in the carb which may effect air cleaner clearance and any hoses that would attach to it. Changing the carb or the intake would probably be the best thing to do, but the adaptor route will be the cheapest and will be fully functional for a mild built motor. It may even add some slight performance by insulating the carb a bit more from the motor heat. This slight improvement is over just cutting up a gasket to make it quick an easy. Tip: My adaptor came with a threaded port in the back for the vacuum line to the brake booster...that will need to be drilled out before it will work. But, my carb had that fitting too, so I just used the one on the carb and left the adaptor undrilled. __________________ He who is without oil shall throw the first rod. Compressions 8.7:1 1972 C10 1976 C10 (parts truck) 1985 K20

09-13-2021, 09:26 PM	#10
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: Carb Gasket You need an adaptor like this. They work either way. Just flip it over. https://www.performance-world.com/Ca...ter-p/2066.htm Tell your son to search for mr. gasket or transdapt name. By the way the dark areas on your spacer indicate the carb was running rich or flooding a bit.

09-13-2021, 09:30 PM	#11
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Re: Carb Gasket Since I'm totally confused on what I have here are some pics. I have more if anyone needs them. Again I don't know if I have a spread bore or a square bore? Attached Images

09-13-2021, 09:59 PM	#12
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,086	Re: Carb Gasket That's technically a "square bore". Take a look at a Q-Jet or Thermo-Quad. They are technically spread bores. Even some old Carter AFB carburetors had larger secondaries. It gets confusing when people lay a label on a lot of stuff, and this carb is a case in point. It could go either way, but I'd call it square bore, personally. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

09-13-2021, 10:12 PM	#13
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: Carb Gasket Buy a Quadra jet and be done with it . __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

09-13-2021, 10:17 PM	#14
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Re: Carb Gasket Thanks for the info, I think i found one on Jegs.

09-13-2021, 10:25 PM	#16
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: Carb Gasket Nothing sounds like a Quadra jet , https://www.youtube.com/watch?v=21NRsuVPrqQ https://www.youtube.com/watch?v=88c-3NYMsvI __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

09-13-2021, 11:55 PM	#19
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: Carb Gasket Here’s two gaskets side by each to compare spreadbore to squarebore. https://www.speedwaymotors.com/Edelb...SABEgL-avD_BwE

09-19-2021, 08:39 PM	#20
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Re: Carb Gasket [COLOR="Red"]Hey, I want to thank everyone for the feedback and input. geezer#99 and everyone else who recommended the carb adapter, found one tried it and it work like a champ. After rebuilding my first carburetor, and a little valve adjustment the ole Chevy fired up today, and ran like a champ. Man I gotta say what a good feeling to hear that old truck after 20+ years sitting ion the garage. Thanks again for the feedback..... [/COLOR]



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09-20-2021, 10:27 PM	#21
burnin oil Registered User Join Date: Jan 2013 Location: Eastern TN Posts: 1,919	Re: Carb Gasket Do you have any stumbles under heavy throttle from idle? I just pulled an adapter like that off of a project truck that had a holley on it. The adapter was about 1/2" thick and made some wicked flow issues. The holley worked flawless but the motor didn't run well. I pulled a qjet out of atleast a 5 year storage and installed it. The motor came alive instantly and power and driveability was way up. Even sounds like a different motor. This thing should have liked the holley better but the adapter and intake killed it. Just a thing to look out for. The front barrels where about 1/3 obstructed by the adapter. I bought the truck this way incase anyone questions my sanity. Good luck.

09-21-2021, 09:56 PM	#22
Bullzak_83 Registered User Join Date: Oct 2020 Location: Arlington,TX Posts: 87	Re: Carb Gasket Hey burnin oil. I have not, BUT I have only just got the engine running last weekend. It has been in my garage for 20+ years. And we are in the process of getting set up for son, he wants a project truck, he now has one.

09-21-2021, 10:56 PM	#24
burnin oil Registered User Join Date: Jan 2013 Location: Eastern TN Posts: 1,919	Re: Carb Gasket And I am still flipping them to this day.

09-21-2021, 11:16 PM	#25
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,512	Re: Carb Gasket You want a real howl, try running 2 quadrajets on a dual quad intake.

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