vacuum line?
Thread Starter
Racer
Joined: Jul 2009
Posts: 350
Likes: 7
From: springstead wi
vacuum line?
with the new carb I have coming , I have one less line hookup . right now im set up with booster to intake , pvc to back of carb then the headlight, vacuum advance, and the trans all have there own port . with the new carb which one should I double up ?
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
PB booster should be by itself from the base of the carburetor at the rear. AT and headlights should be from a intake manifold fitting. Distributor should run directly from the carb on its own line. PCV has its own port.
Thread Starter
Racer
Joined: Jul 2009
Posts: 350
Likes: 7
From: springstead wi
the carb has 3 ports .
says 1 for pvc or brake booster
1 for spark advance
1 that's full vacuum
then I have the one that's on the intake.
so if I hook the booster to the back of the carb were does the pvc go ?
says 1 for pvc or brake booster
1 for spark advance
1 that's full vacuum
then I have the one that's on the intake.
so if I hook the booster to the back of the carb were does the pvc go ?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You can hook the brake booster to the intake manifold IF the fitting is large enough to feed the booster. It should be as large as the one getting the PCV line. You should NOT hook those two lines together.
Burning Brakes
Joined: Aug 2008
Posts: 878
Likes: 55
From: Deep South Denmark
Most importantly the PCV must be hooked to the base of the carb (because of the constant flow of air through it).
There is nothing wrong with connecting the brake booster to the manifold, it was connected there on early models.
There is nothing wrong with connecting the brake booster to the manifold, it was connected there on early models.
Thread Starter
Racer
Joined: Jul 2009
Posts: 350
Likes: 7
From: springstead wi
so the 3 I have left with 2 ports which two do I put together , have trans , spark advance and headlights . so if I put the spark on one and the trans on the other where do I hook up the headlights ?
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Burning Brakes
Joined: Mar 2013
Posts: 1,018
Likes: 582
From: West Monroe Louisiana
2023 C3 of the Year Finalist - Unmodified
carb on the metal tube with the rubber on the end.
The transmission and vacuum lines to the headlights are on the
fitting with the two outlets on the intake manifold.
I have mechanical advance and don't use the vacuum line on the side
of the carb that is plugged off.
Donnie
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
I'm not going to pretend that I can tell you the CORRECT way to hook up all of your vacuum lines. The reason is because I made a vacuum "tree" off of the big port on the rear of my Holley 650 DP. I run EVERYTHING except the distributer vacuum can off of that port. 
Contrary to popular belief all items work correctly. My brakes are rock hard. My cam makes very decent vacuum which helps also.
You should have some type of threaded port on your intake manifold to install one of these...
http://www.jegs.com/i/JEGS+Performan...16005/10002/-1
That will give you some more options for hooking up your lines AND it will fit under the rear float bowl of a 4150 Holley carb if your port is located there.
Contrary to popular belief all items work correctly. My brakes are rock hard. My cam makes very decent vacuum which helps also.
You should have some type of threaded port on your intake manifold to install one of these...
http://www.jegs.com/i/JEGS+Performan...16005/10002/-1
That will give you some more options for hooking up your lines AND it will fit under the rear float bowl of a 4150 Holley carb if your port is located there.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Brake booster connected with other items will work. The concern is that there could be some cross-contamination from one system to the other, as each may need or vent vacuum at different times. Thus, there will be some small amount of 'flow' in those lines, and it would be a concern to get fuel vapor/oil vapor contaminants into the brake booster. Little risk of short-term damage; more concern about long-term [seal] damage.
As mentioned before, it would be BEST to keep the booster on a separate [and larger] line.
As mentioned before, it would be BEST to keep the booster on a separate [and larger] line.