How to vent Edelbrock carb? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gregbr · 08-16-2005, 12:23 PM

This may be a stupid question, but I will ask anyway. How do you "properly" vent an Edelbrock 1406 carb? Mine has the vent plugged (by P.O.). It runs fine, just don't seem right.

Jakes-66-K10 · 08-16-2005, 01:17 PM

I just got a 1406, and never heard of this. What is "venting"? Are you referring to the threaded plug in the back? That's about the only thing I can think of to plug...

extd56 · 08-16-2005, 01:43 PM

I have an Edelbrock carb with a vent too, right by where the gas goes in the carb. The PO have it vented to the side of the motor, it worked. I would think you would want to suck it back into the carb. I believe only the old Edelbrock carbs have this feature.

**pjmoreland** · 08-16-2005, 04:04 PM

The Edelbrock 1400 (complies with California emissions standards) has a vent connection that points down slightly, over on the passenger side of the carburetor. I suspect it's supposed to be connected to a charcoal canister.

**'68OrangeSunshine** · 08-17-2005, 05:20 AM

The downward inlet is for the EGR valve. Same as the Carter 9635. Had one on a 454 in a '67 Sub. PO capped it off.

gregbr · 08-17-2005, 12:00 PM

Don't know where it's supposed to hook, but it IS a vent with an internal valve that is open when the carb is at idle. Makes sense to hook it to a charcoal canister or maybe the PCV. Don't seem like a good idea to build up pressure on the floats etc.

**'68OrangeSunshine** · 08-18-2005, 04:31 AM

PCV already is plumbed in thru the input in the center, between the mixture screws.

gregbr · 08-18-2005, 07:48 PM

Yes, I realize the PCV connection is in the front center, it's been hooked up. I'm talking about the carb bowl vent that is the angled connection you wrote about earlier. It should be vented somewhere to relieve pressure from the fuel bowl of the carb. But these older trucks don't have an EGR or a charcoal canister.

**'68OrangeSunshine** · 08-19-2005, 06:55 AM

In my situation, I left it the way the PO set it up. The EGR tap was plugged off with a big rubber cap. Since it was on a '67 truck, there was no EGR in the system. The 454 seemed to run OK the way it was. It's over my head what that pressure is doing to the inner workings of an AFB type carb. It is an interesting question. I wonder what would happen if you plumbed the EGR tap to breathe thru the air cleaner? Would it blow up? Gum up the carb? Or would you be able to burn a little more hydrocarbons? Obviously I'm no carb expert, I'm just on here to learn. I read in a Carter tuning book that carbs for marine use used the downward pointing inlet as a gas input.

08-16-2005, 12:23 PM	#1
gregbr Senoir Member Join Date: Mar 2002 Location: Rock Hill, SC USA Posts: 1,214	How to vent Edelbrock carb? This may be a stupid question, but I will ask anyway. How do you "properly" vent an Edelbrock 1406 carb? Mine has the vent plugged (by P.O.). It runs fine, just don't seem right. __________________ 67 Chevy, Small back glass, Factory 4WD, Factory Shortbed, Factory V8, Lifted 4" 70 GMC Sierra Grande, Factory Shortbed, Factory 402/400 turbo, Super Custom Interior. Numbers matching with SPID & Build Sheet. 68K Original Miles. Restored 2010 70 GMC Restoration Pictures http://67-72chevytrucks.com/gallery/...00&ppuser=4424

08-16-2005, 04:04 PM	#4
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,982	The Edelbrock 1400 (complies with California emissions standards) has a vent connection that points down slightly, over on the passenger side of the carburetor. I suspect it's supposed to be connected to a charcoal canister. Attached Images Last edited by pjmoreland; 08-16-2005 at 04:06 PM.

08-17-2005, 05:20 AM	#5
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	The downward inlet is for the EGR valve. Same as the Carter 9635. Had one on a 454 in a '67 Sub. PO capped it off. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 08-17-2005 at 05:22 AM.

08-17-2005, 12:00 PM	#6
gregbr Senoir Member Join Date: Mar 2002 Location: Rock Hill, SC USA Posts: 1,214	Don't know where it's supposed to hook, but it IS a vent with an internal valve that is open when the carb is at idle. Makes sense to hook it to a charcoal canister or maybe the PCV. Don't seem like a good idea to build up pressure on the floats etc. __________________ 67 Chevy, Small back glass, Factory 4WD, Factory Shortbed, Factory V8, Lifted 4" 70 GMC Sierra Grande, Factory Shortbed, Factory 402/400 turbo, Super Custom Interior. Numbers matching with SPID & Build Sheet. 68K Original Miles. Restored 2010 70 GMC Restoration Pictures http://67-72chevytrucks.com/gallery/...00&ppuser=4424

08-18-2005, 04:31 AM	#7
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	PCV already is plumbed in thru the input in the center, between the mixture screws. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

08-16-2005, 01:17 PM	#2
Jakes-66-K10 Registered User Join Date: Aug 2004 Location: Idaho Posts: 640	I just got a 1406, and never heard of this. What is "venting"? Are you referring to the threaded plug in the back? That's about the only thing I can think of to plug...

08-16-2005, 01:43 PM	#3
extd56 Senior Member Join Date: Nov 2004 Location: Vacaville, CA Posts: 2,272	I have an Edelbrock carb with a vent too, right by where the gas goes in the carb. The PO have it vented to the side of the motor, it worked. I would think you would want to suck it back into the carb. I believe only the old Edelbrock carbs have this feature.

08-18-2005, 07:48 PM	#8
gregbr Senoir Member Join Date: Mar 2002 Location: Rock Hill, SC USA Posts: 1,214	Yes, I realize the PCV connection is in the front center, it's been hooked up. I'm talking about the carb bowl vent that is the angled connection you wrote about earlier. It should be vented somewhere to relieve pressure from the fuel bowl of the carb. But these older trucks don't have an EGR or a charcoal canister. __________________ 67 Chevy, Small back glass, Factory 4WD, Factory Shortbed, Factory V8, Lifted 4" 70 GMC Sierra Grande, Factory Shortbed, Factory 402/400 turbo, Super Custom Interior. Numbers matching with SPID & Build Sheet. 68K Original Miles. Restored 2010 70 GMC Restoration Pictures http://67-72chevytrucks.com/gallery/...00&ppuser=4424

08-19-2005, 06:55 AM	#9
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	In my situation, I left it the way the PO set it up. The EGR tap was plugged off with a big rubber cap. Since it was on a '67 truck, there was no EGR in the system. The 454 seemed to run OK the way it was. It's over my head what that pressure is doing to the inner workings of an AFB type carb. It is an interesting question. I wonder what would happen if you plumbed the EGR tap to breathe thru the air cleaner? Would it blow up? Gum up the carb? Or would you be able to burn a little more hydrocarbons? Obviously I'm no carb expert, I'm just on here to learn. I read in a Carter tuning book that carbs for marine use used the downward pointing inlet as a gas input. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 08-19-2005 at 06:58 AM.



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