6 bbl qs

[copper01]

340 6bbl engine----------I have been getting the kinks out my car and now a new head scratcher arrives. I had the air cleaner off tonight and I noticed I have no vaccum line going to the distributor. Its a 340 6 pack,4 speed car. The car runs good but has no hose going to the vaccum advance.  Is this common on 6 packs? Or is there a advantage or dis advantage?
If there should be a hose does anyone have a pic of how it SHOULD be?   It runs good but I prefer to have things how they should be.  Thanks

[Chryco Psycho]

Vacuum advance is more for emissions , most engine respond better with total timing around 36* & idles around 16 with no vacuum advance connected . I bet performance will be worse with the vacuum advance connected , if you want the stock look slide a small ball brg inside the hose

[1 Wild R/T]

Vacuum advance is more for emissions , most engine respond better with total timing around 36* & idles around 16 with no vacuum advance connected . I bet performance will be worse with the vacuum advance connected , if you want the stock look slide a small ball brg inside the hose

If this were true explain to me why one of the first things manufacturers did on early emissions controlled vehicles was disable the vacuum advance....

When properly set up vacuum advance improves fuel economy...  You still shoot for total mechanical advance in the 34-36 degree range but by adding another 14-18  degrees with the vacuum advance you get a total under light throttle cruise of 48-54 degrees... As soon as you get on the throttle venturi/manifold vacuum falls so the vacuum controlled timing falls out & you revert to the mechanical curve.....

On a Sixpack look at the passenger side of the center carb.. There should be hoses connecting the center carb to the outboard vacuum pods and directly below that is the vacuum advance port...

[AMXguy]

I run 18 degrees of manifold port vac advance on my 440 six pack and it works perfect.  12 initial, 34 all in mechanical and 18  so it's at 52 cruise speed.    I'm sure you don't have to but it runs smoother and gets better mileage.

This is the best read on vac advance written.

http://www.camaros.org/pdf/timing101.pdf

[Chryco Psycho]

With anything other than the stock cam you need to shorten the advance cuve so more initial with the same total timing , I have never found an increase in milage with the vacuum advance connected .
 So maybe  the vacuum advance as an emission help is the wrong term but it is not adding power

[734406pk]

340 6bbl engine----------I have been getting the kinks out my car and now a new head scratcher arrives. I had the air cleaner off tonight and I noticed I have no vaccum line going to the distributor. Its a 340 6 pack,4 speed car. The car runs good but has no hose going to the vaccum advance.  Is this common on 6 packs? Or is there a advantage or dis advantage?
If there should be a hose does anyone have a pic of how it SHOULD be?   It runs good but I prefer to have things how they should be.  Thanks

Are you running a stock cam in this engine?

[copper01]

non stock cam..   I would like to get these dialed in before i install a four barrell.  I think im use to more power thats my biggest problem. The 3.23 gears take the fun out of driving it in town. A good set of gears may do more good than anything for me.

[Chryco Psycho]

There is a Holley tuning guide in the Archives so startworking through that , the 6 pack acts just like a 4 bbl as long as you think of the outboard carbs as the secondaries ,
 Start with float levels then  with vacuum readings , you need to know what vacuum you have at idle in gear & match the powervalve to that so if you have 6" in gear you need a 3.5 or 4.5 " powervalve   

[copper01]

There is a Holley tuning guide in the Archives so startworking through that , the 6 pack acts just like a 4 bbl as long as you think of the outboard carbs as the secondaries ,
 Start with float levels then  with vacuum readings , you need to know what vacuum you have at idle in gear & match the powervalve to that so if you have 6" in gear you need a 3.5 or 4.5 " powervalve

Thanks.  Weekend project planned .. Thanks again

[Chryco Psycho]