Edelbrock vaccum line placement - The 1947 - Present Chevrolet & GMC Truck Message Board Network

my new 72 · 09-24-2002, 09:20 AM

I am running an edelbrock 1411 and I need to know exactly where the vaccume lines should be placed. I have three ports on the front, and I know the one in the middle goes to a T-fitting that goes from the can to the pcv valve, but what about the other two. One is supposed to go to the Vac advance on the Dist. and the other to the can, but I checked the Vac to them both and one reads 10 at idle and the other reads 16. Should the Dist vac advance be connected to the one that reads 16? Right now it is connected to the one that reads 10 and I am having a few problems with it not idleing smooth it jumps between 575 and 650 when in gear. Anyone have any idea.

bigjimzlll · 09-24-2002, 03:06 PM

the one on the passenger side is the ported vacuum, the one on the driver side is full manifold vacuum. I use the full manifold vacuum, for my distributer,..the higher vac. at idle smoothes out the engine and as you increase the throttle, the mechanical advance takes over and the vacuum decreases. If you use the ported one, as you accelerate the vacuum increases as the mechanical advance increases and advances the timing too much

tom hand · 09-24-2002, 03:53 PM

How much vacuum does your motor hold in gear if you read it straight off the manifold? From what you said, your ported vacuum port is reading 10 inches at idle which makes me think your trottle blades are almost past the idle circuit. You may need to go to lighter springs on your metering rods so it won't go into the power circuit at idle. How "wild" is your cam?

my new 72 · 09-24-2002, 03:59 PM

The cam isn't too wild. It a crane energizer 274. The published numbers are 218 deg duration at .454 lift. Not too much, it should idle smoother than it does. Shouldn't it? If the cam is gonna make it idle a little rough then that's okay, but if not I would like to adjust it properly to where it will run the way it should.

tom hand · 09-24-2002, 04:06 PM

Well you said one of your vacuum ports was 16 inches @ idle. That is right on the edge. I would try lighter springs, they cost very little and take 2 minutes to change.

my new 72 · 09-24-2002, 04:14 PM

Sounds good. Thanks for the info.

09-24-2002, 09:20 AM	#1
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	Edelbrock vaccum line placement I am running an edelbrock 1411 and I need to know exactly where the vaccume lines should be placed. I have three ports on the front, and I know the one in the middle goes to a T-fitting that goes from the can to the pcv valve, but what about the other two. One is supposed to go to the Vac advance on the Dist. and the other to the can, but I checked the Vac to them both and one reads 10 at idle and the other reads 16. Should the Dist vac advance be connected to the one that reads 16? Right now it is connected to the one that reads 10 and I am having a few problems with it not idleing smooth it jumps between 575 and 650 when in gear. Anyone have any idea. __________________ I'm going to Law School, wanna debate? It's good practice.

09-24-2002, 03:06 PM	#2
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	the one on the passenger side is the ported vacuum, the one on the driver side is full manifold vacuum. I use the full manifold vacuum, for my distributer,..the higher vac. at idle smoothes out the engine and as you increase the throttle, the mechanical advance takes over and the vacuum decreases. If you use the ported one, as you accelerate the vacuum increases as the mechanical advance increases and advances the timing too much __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

09-24-2002, 03:53 PM	#3
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	How much vacuum does your motor hold in gear if you read it straight off the manifold? From what you said, your ported vacuum port is reading 10 inches at idle which makes me think your trottle blades are almost past the idle circuit. You may need to go to lighter springs on your metering rods so it won't go into the power circuit at idle. How "wild" is your cam? __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-24-2002, 03:59 PM	#4
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	The cam isn't too wild. It a crane energizer 274. The published numbers are 218 deg duration at .454 lift. Not too much, it should idle smoother than it does. Shouldn't it? If the cam is gonna make it idle a little rough then that's okay, but if not I would like to adjust it properly to where it will run the way it should. __________________ I'm going to Law School, wanna debate? It's good practice.

09-24-2002, 04:06 PM	#5
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Well you said one of your vacuum ports was 16 inches @ idle. That is right on the edge. I would try lighter springs, they cost very little and take 2 minutes to change. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-24-2002, 04:14 PM	#6
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	Sounds good. Thanks for the info. __________________ I'm going to Law School, wanna debate? It's good practice.



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