6bbl set up

[ksurfer2]

I have a 6bbl set up on the 440 in my 69 RR. The car runs great with plenty of power, but I am wondering about the set up of the vacuum lines. There is no vacuum advance hooked up to the distributor, and that is part of the reason for this post. Below are some pics of my set up and a set up that I pulled off line. There are some differences in the way the vacuum lines are hooked up.

This is a picture that I pulled off line. the vacuum line running the advance on the distributor is coming off the top of the middle carb. The vacuum running the outboard carbs is coming from below that.

Here are my carbs...The vacuum running the outboard carbs is coming from the top of the center carb. There is no additional vacuum port on the carb to hook up an advance for the distributor.

Lastly...here are two capped off lines coming out of the back of the intake manifold. should these be connected to anything?

Any advice on how to properly set all of this up will be greatly appreciated.

 

[lewtot184]

the vacuum advance line comes off a nipple sticking out from the metering block; the end carb vacuum lines hook to a nipple sticking out from the center carb body. the vacuum fitting in back of the manifold would used for power brakes.

 

[ksurfer2]

the vacuum advance line comes off a nipple sticking out from the metering block; the end carb vacuum lines hook to a nipple sticking out from the center carb body. the vacuum fitting in back of the manifold would used for power brakes.

OK...so the vacuum port that my end carbs are currently hooked to should be running the vacuum advance for the distributor. Correct? I will have to look closer for an additional vacuum port as I did not see one when I was looking yesterday.

 

[Bill Monk]

There are 4 ports on a center carb.
Larger port is obviously for PCV
Bottom port (under fuel bowl) attaches to the choke pull off
middle port (tight near choke pulloff dashpot) is for the 2 outboards
Upper port in a stock setup is for the ported vac advance
I hook my distributor advance to the lower port for max performance and plug the upper port (i'm sure this will re-open another conversation on vacuum advance) but as far as I am concerned, that's the right way to do it.

 

[ksurfer2]

There are 4 ports on a center carb.
Larger port is obviously for PCV
Bottom port (under fuel bowl) attaches to the choke pull off
middle port (tight near choke pulloff dashpot) is for the 2 outboards
Upper port in a stock setup is for the ported vac advance
I hook my distributor advance to the lower port for max performance and plug the upper port (i'm sure this will re-open another conversation on vacuum advance) but as far as I am concerned, that's the right way to do it.

So if I am reading this correctly, there is another vacuum port under where my 2 outboards are currently hooked up that I have not seen (i have been looking at a lot of pics on other sites and it should be there). This port is where the outboards should be hooked up to...Correct? Since I am currently not running vacuum advance on my distributor, I should block off the upper port.

If I make these changes, what effect (if any) will there be on the car's performance?

 

[lewtot184]

OK...so the vacuum port that my end carbs are currently hooked to should be running the vacuum advance for the distributor. Correct? I will have to look closer for an additional vacuum port as I did not see one when I was looking yesterday.

I can't see precisely what you have with your picture; but the vacuum advance hose hooks to the nipple on the side of the metering block.

 

[Bill Monk]

I can't see precisely what you have with your picture; but the vacuum advance hose hooks to the nipple on the side of the metering block.

Lewtot is right, the factory vac advance port is the only one that comes off the metering block and yes if you don't run advance then plug it off. The one for the outboards is tight and near the choke pulloff dashpot and the last one is on the very bottom (throttle plate) and connects to the dashpot

 

[dadeo]

Maybe this will help.
Red is to PVC on valve cover (larger diameter line)
Green is for outboard carbs vacuum dashpots
Blue is for distributor vacuum advance
Yellow is choke

 

[ksurfer2]

Maybe this will help.
Red is to PVC on valve cover (larger diameter line)
Green is for outboard carbs vacuum dashpots
Blue is for distributor vacuum advance
Yellow is choke
View attachment 590185

Yes...Thank you.

 

[TOMRR]

 

[ksurfer2]

What is the large vacuum line coming out of the top of the center carb in your photo? My center carb does not have a port there (nor does the carb in the pics I pulled off the web).

 

[rarefish]

What is the large vacuum line coming out of the top of the center carb in your photo? My center carb does not have a port there (nor does the carb in the pics I pulled off the web).

That hose is just for the center carb bowl vent. The early center carbs did not have them. The other end of that hose connected to a nipple that was located on the passenger side valve cover breather.

 

[383man]

One thing to remember is the end carbs vacuum pods have to have venturi vacuum to work right. So if you ever want to be sure they are hooked to the right port hook a vacuum gauge up to the port on the center carb that should be for the end carb vacuum pods. Then check the vacuum when you drive the car as the venturi vacuum should get stronger the more you step on the gas and the more the eng speeds up. At wide open throttle venturi vacuum should be strong and high. All other vacuum ports should be manifold vacuum as even the ported vacuum advance port is manifold vacuum but its just above the throttle plates. All the other vacuum ports should be strong at part throttle but drop to zero or very close to zero vacuum at wide open throttle. Ron

 

[ksurfer2]

So I had a chance to take a closer look at my set up. On the center carb, there is only 1 vacuum port coming out of the metering block that the outboard carbs are currently hooked up to. There are no additional vacuum ports. The number stamped on the metering block is 6525 4782. The only numbers I could find stamped on the carbs are 1565 R3589 these numbers are stamped on the top of the carb. I could find no reference to carbs on the web with these numbers. On the base of the carb is 4782. According to a Holley reference page this is a 355 cfm carb. Sound right?

At idle and when reving the engine and looking at the outboard carbs, no fuel is going though them. I would assume this is normal?

I am not sure where to go from here.

 

[dadeo]

Correct, only 1 vacuum port out of the metering block but for distributor advance.
Since my car is not available to take you some up close-up pics what the guys in previous posts are saying is exactly right. The 1 on the metering block is for your vacuum advance and the one on the center carb main body is for the outboard carbs vacuum signal. Took these pics from the service manual.
350cfm on center carb, 500cfm on outboards (440 application)
340 manual trans center carb, 4791, that carb has a 355 CFM rating (I believe)
Since the outboard carbs don't have accelerator pumps you will not see the shot of fuel like the center carb does when you rev it.

 

[ksurfer2]

The vacuum port on the first pic above is not present on my center carb. That is where I am a bit lost.

 

[Bill Monk]

The vacuum port on the first pic above is not present on my center carb. That is where I am a bit lost.

Unless it's been removed and I don't know why anybody would do that, it has to be. I'm confused now. can you take a good picture of your carb on that side from a few angles and post?

 

[ksurfer2]

Does this help? If not I can get another pic with the vacuum line removed for a better view

 

[dadeo]

Almost looks like someone removed and plugged it but hard to see in your pic. Maybe disconnect that vacuum line and move it out of the way and take another close up.

 

[dadeo]

So if you don't have that provision the only thing I can think of is the main body of the carb is the old style Direct Connection mechanical carb with the right fuel bowl that someone put together.