edelbrock 1405 question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

doughby82 · 12-19-2003, 04:56 AM

there is 2 vaccum ports on the front.one goes to the vac adv.the other one goes under the firewall ontop of the tranny i havent looked to see where it goes from there,if memory recall me right on my last one one went to the van adv. and the other was plugged.can someone shed some light.also its on a 350/th350

JayDubBlazer · 12-19-2003, 06:38 AM

I think that my right one as you are looking at it goes to the dist, while the left one is plugged

70ChevyLongbed · 12-19-2003, 10:44 AM

On my 1404 I have the driver side running to the Dist and the passanger side plugged. I was told that the passanger side could go to the vaccum for the tranny. The vac for the tranny on mine runs to a tree out of the intake behind the carb.

From Edelbrock Tech tips: "6. To select the proper distributor vacuum port on your Edelbrock carburetor, we suggest the following procedure to locate the correct outlet. Before removing your old carburetor (with the engine warmed up to operating temperature and idling), pull the hose off the port that routes to the distributor vacuum advance canister. After the hose has been removed from the carb, place your finger over the vacuum outlet. If, (at idle), you feel your finger being sucked in toward the carburetor, you have full-time vacuum advance. If you don't feel any vacuum pulling at your finger with the engine at an idle, you have timed/ported vacuum advance. "

Huck · 12-19-2003, 11:13 AM

Your turbo30 transmission requires full manifold vacuum to it's vacuum modulator on the back of the transmission. It usually has a solid metal tube running up to the intake and run off of a tee from a fitting on the back of the intake manifold. That tee sometimes feeds the heater control and the power brakes.

The 2 ports on the front of the edelbrock carb are for the vac advance to the distributor. Depending on which distributor you have--some HEI distributors prefer running off timed vacuum which would be the port with no vacuum at idle. For other HEIs and the original stock ignition system you need to run off of full manifold vacuum which will be sucking pretty hard at idle. Just be sure there are no leaks.

12-19-2003, 04:56 AM	#1
doughby82 Registered User Join Date: Mar 2001 Location: springfield ill Posts: 836	edelbrock 1405 question there is 2 vaccum ports on the front.one goes to the vac adv.the other one goes under the firewall ontop of the tranny i havent looked to see where it goes from there,if memory recall me right on my last one one went to the van adv. and the other was plugged.can someone shed some light.also its on a 350/th350 __________________ springfield illinois 2003 custom (harley)built from scratch 68 swb

12-19-2003, 06:38 AM	#2
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,885	I think that my right one as you are looking at it goes to the dist, while the left one is plugged __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT Last edited by JayDubBlazer; 12-19-2003 at 06:51 AM.

12-19-2003, 10:44 AM	#3
70ChevyLongbed Howzit?!? Join Date: Jan 2003 Location: Maryville, TN Posts: 1,266	On my 1404 I have the driver side running to the Dist and the passanger side plugged. I was told that the passanger side could go to the vaccum for the tranny. The vac for the tranny on mine runs to a tree out of the intake behind the carb. From Edelbrock Tech tips: "6. To select the proper distributor vacuum port on your Edelbrock carburetor, we suggest the following procedure to locate the correct outlet. Before removing your old carburetor (with the engine warmed up to operating temperature and idling), pull the hose off the port that routes to the distributor vacuum advance canister. After the hose has been removed from the carb, place your finger over the vacuum outlet. If, (at idle), you feel your finger being sucked in toward the carburetor, you have full-time vacuum advance. If you don't feel any vacuum pulling at your finger with the engine at an idle, you have timed/ported vacuum advance. " __________________ Jason Hawaiian-J 70 Longbed, 307, Edelbrock Carb 1404, Edelbrock Intake 2101, Dual Roller Timing chain and gears, 214/214 cam, Comp Roller Rockers, dual Flowmasters. 1999 Chevy Tahoe 2004 Mini Cooper S 71 BMW 2002 - Sold

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12-19-2003, 11:13 AM	#4
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,269	Your turbo30 transmission requires full manifold vacuum to it's vacuum modulator on the back of the transmission. It usually has a solid metal tube running up to the intake and run off of a tee from a fitting on the back of the intake manifold. That tee sometimes feeds the heater control and the power brakes. The 2 ports on the front of the edelbrock carb are for the vac advance to the distributor. Depending on which distributor you have--some HEI distributors prefer running off timed vacuum which would be the port with no vacuum at idle. For other HEIs and the original stock ignition system you need to run off of full manifold vacuum which will be sucking pretty hard at idle. Just be sure there are no leaks.



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