Modifications
Thread Starter
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Modifications
Replaced existing Moroso valve covers with the proper aluminum finned covers, and of course that meant I had to hook up the closed PCV valve system that was used with them. Unfortunately, the previous owner
replaced the stock quadrajet with a Holley 4160 DP, so there are a few mods I need to make. It looks as if I can hook up the drivers side that has the PCV valve to the back of the Holley 4160 port that I believe
was used for power brakes. In the front of the Holley there is a smaller vacuum port that I was thinking could be used for my vac advanced rather than the existing ported vacuum fitting near the top of the carb
on the passenger side. Am I correct in thinking this way?
replaced the stock quadrajet with a Holley 4160 DP, so there are a few mods I need to make. It looks as if I can hook up the drivers side that has the PCV valve to the back of the Holley 4160 port that I believe
was used for power brakes. In the front of the Holley there is a smaller vacuum port that I was thinking could be used for my vac advanced rather than the existing ported vacuum fitting near the top of the carb
on the passenger side. Am I correct in thinking this way?
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
4160 is probably not a DP. Those are usually 4150.
You can use the intake manifold fitting to hook up the power brake booster.
The vacuum advance can also be hooked up to the same intake manifold fitting. This is a "manifold" vacuum advance, not a "ported" vacuum advance (from above the carb butterflies). This is a preferred setup.
The PCV should be hooked up to the large carb base fitting.
The carb fitting for ported vacuum advance can be plugged
You can use the intake manifold fitting to hook up the power brake booster.
The vacuum advance can also be hooked up to the same intake manifold fitting. This is a "manifold" vacuum advance, not a "ported" vacuum advance (from above the carb butterflies). This is a preferred setup.
The PCV should be hooked up to the large carb base fitting.
The carb fitting for ported vacuum advance can be plugged
Last edited by stingr69; Sep 27, 2019 at 07:47 AM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Make sure the other valvecover has a way of allowing fresh air into the crankcase, such as a breather cap of your choice. Otherwise the PCV is doing nothing.
stingr69 is right. PB booster should get a solo line. A "dedicated" Vac line is a must for proper brake function.
The PCV vac line can be hooked to the carb base plate as mentioned. That makes all the cylinders get some oil mist from the PCV valve. If hooking it up the Intake, then only one cyl gets the oil mist, I believe #6?
The Vac fitting on the Intake can be swapped out from a single to a dual, or triple port fitting if that helps:
Headlights
HVAC
Auto Tranny
Dizzy
etc.
stingr69 is right. PB booster should get a solo line. A "dedicated" Vac line is a must for proper brake function.
The PCV vac line can be hooked to the carb base plate as mentioned. That makes all the cylinders get some oil mist from the PCV valve. If hooking it up the Intake, then only one cyl gets the oil mist, I believe #6?
The Vac fitting on the Intake can be swapped out from a single to a dual, or triple port fitting if that helps:
Headlights
HVAC
Auto Tranny
Dizzy
etc.
Thread Starter
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Thanks for the replies. Looking at my post, I didn't explain the situation very clearly. My car doesn't have power brakes, I was just thinking of hooking the driver side PCV valve to the back base of the Holley that many use
for the power brakes. This port is larger in size then the port on the front of the carb and matches the size of the PCV valve rubber hose so I thought this would be ideal.
for the power brakes. This port is larger in size then the port on the front of the carb and matches the size of the PCV valve rubber hose so I thought this would be ideal.
