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Vacuum Diagrams Restomod Edition


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Hi all! My question is directed towards how everyone else has their vacuum lines set up based on the modifications they've applied to the cars i.e. new intakes, EGR eliminated, vacuum canister eliminated, Newer distributors, the list goes on... I know of and have viewed the diagrams provided by @Don C and all those who've contributed to building a concourse car. I'm more interested to see what everyone's done to bypass certain parts of the diagrams or which parts are the diagram are critical vs. major to the operation based on the set up someone is running. Does everyone here really have 3-hose ported vacuum, solenoid valves, and/or spark delay valves? Ex: How did you set up the Ram-air vacuum lines with deleted parts of a diagram, did this affect your timing, what subtle changes did you notice after testing, do you have documentation to share? 

Rather than relying on a manufacturer's, i.e. Holley, Edelbrock, Petronix, recommendation i'd prefer the testimony of my community where everyone here has a unique set up that can provide variable data.

Critical Characteristic: component that is necessary to the form, fit, and function of the engine and or/timing.

Major Characteristic: component that is necessary for emissions control, but does not have an effect on form, fit and function of the engine and/or timing.

Rather than relying on a manufacturer's, i.e. Holley, Edelbrock, Petronix, recommendation i'd prefer the testimony of my community where everyone here has a unique set up that can provide variable data.

thank you all!

 

 

1972 Mach1 H-code 351C - 2V - bought 10/5/2010 still a headeache

1972 Grande coupe Inline 6 1bbl - dad bought in 90's Sold

 

 

 

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Two items are necessary, crankcase ventilation (PCV) and distributor vacuum (unless you have a centrifugal advance only distributor) directly from carburetor to the distributor. If you have the original air cleaner you'll also want to retain the vacuum to the flapper in the intake snout.

The ram air and flapper can both be plumbed directly from the intake manifold. As long as you don't have any vacuum leaks in the vacuum motors they won't affect the timing or carburetor fuel/air ratios.

Edit: If you have an automatic transmission you'll also need vacuum to the vacuum modulator.

Edited by Don C
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“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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When I got my car, it was in a field with everything under the hood gone.  I guess you could say the last guy who had it did all the vacuum delete for me.  :biggrin:

I put the car together 1 piece at a time.  Crate 351 long block, edlebrock intake, holley carb, C4 transmission I had kicking around.  

As far as vacuum goes, I have a fitting in the intake manifold running the large hose directly to the power brake booster.  Aftermarket carbs have one or more places to connect to pull vacuum from manifold or ported.  Its a 4 hour conversation if you want to run your distributor from ported or manifold vacuum.  There are guys who feel strongly both ways.  And you can tune a car and get good performance no matter which strategy you go with.  Whichever one you choose, plug the hose from your distributor to that port on the carb.  The distributor I used has the retard port on it and I just left that capped.  On our automatic transmissions, there's a vacuum line going to the transmission modulator.  It needs to be connected to full manifold vacuum.  You can tee it in to your distributor line if that one is also using manifold vacuum and you dont have any more ports on the carb.

Then I have the big port on the back of the carb running to the PCV fitting on one valve cover.  Other valve cover is pulling filtered air from the air cleaner.

 

My car does not have the heater hooked up.  I'll be using an aftermarket AC, so I dont think those vacuum lines will be necessary.

My ram air kit is not installed.  When I do put it on, I reckon it'll need manifold vacuum, so I'll tee off an existing line if I don't have a free port.

 

 

Edited by giantpune
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12 hours ago, Don C said:

Two items are necessary, crankcase ventilation (PCV) and distributor vacuum (unless you have a centrifugal advance only distributor) directly from carburetor to the distributor. If you have the original air cleaner you'll also want to retain the vacuum to the flapper in the intake snout.

The ram air and flapper can both be plumbed directly from the intake manifold. As long as you don't have any vacuum leaks in the vacuum motors they won't affect the timing or carburetor fuel/air ratios.

for the PCV is it critical to have it connected to the back of the carburetor or can it be a breather cap? As far as the dizzy, the option is available to connect dizzy>> 3way port> intake & carb. can the 3 way port be eliminated? 

1972 Mach1 H-code 351C - 2V - bought 10/5/2010 still a headeache

1972 Grande coupe Inline 6 1bbl - dad bought in 90's Sold

 

 

 

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13 hours ago, giantpune said:

Whichever one you choose, plug the hose from your distributor to that port on the carb.  The distributor I used has the retard port on it and I just left that capped.  On our automatic transmissions, there's a vacuum line going to the transmission modulator.  It needs to be connected to full manifold vacuum.  You can tee it in to your distributor line if that one is also using manifold vacuum and you dont have any more ports on the carb.

I did exactly that, I have my dizzy line connected to the ported line next to the meter block from the carb. however the amount of vacuum from the manifold (RPM AIR GAP) showed the same readings from the port underneath the carb (750CFM quickfuel) i guess its a matter of preference.

13 hours ago, giantpune said:

Then I have the big port on the back of the carb running to the PCV fitting on one valve cover.  Other valve cover is pulling filtered air from the air cleaner.

My ram air kit is not installed.  When I do put it on, I reckon it'll need manifold vacuum, so I'll tee off an existing line if I don't have a free port.

 

 

also did the samething i that of it as a major concern towards having fumes in the cabin so i too ran the passenger side PCV line into the carb, but I'm running a breather cap on the drivers side valve cover to eliminate so many hoses and lines everywhere. all these vacuum lines and circulation lines almost makes the car look like a birds nest. lol

1972 Mach1 H-code 351C - 2V - bought 10/5/2010 still a headeache

1972 Grande coupe Inline 6 1bbl - dad bought in 90's Sold

 

 

 

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25 minutes ago, kiko619 said:

for the PCV is it critical to have it connected to the back of the carburetor or can it be a breather cap? As far as the dizzy, the option is available to connect dizzy>> 3way port> intake & carb. can the 3 way port be eliminated? 

The PCV valve is inserted into the top of one of the caps on the valve covers and the hose runs to the PVC port on the carburetor or adapter under the carburetor. The other cap has a hose run from it to the air cleaner to supply filtered air to the crankcase. Eliminate the 3 way port, remove it and plug it with a pipe plug (3/8" I believe).

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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