Vacuum line dilemna

[scivies]

I hope one of you fine folks could point me in the right direction. My original Quadrajet is long gone and was replaced by the previous owner with a spread-bore Holley. The problem is some of the vacuum lines do not appear to be correct. According to the Holley website, the large rear connection goes to the power brake booster and the small front connection goes to the vacuum advance on the distributor. Does anyone know how the other 3-pronged lines in the intake manifold get connected? More importantly, which lines go to the EGR valve and heater control valve? Any assistance would be greatly appreciated.

[Robroy]

Hi Scivies,

Being a foreigner I’m a bit uncertain of what you mean when you say 3-pronged lines?

Below is a pict of my 455 on which you can see the temp controlled vacuum switch from which three lines are connected, one to the dist another to the carb and the third to some black plastic can in the corner of the engine bay…:confused:
As you might notice the airpump is removed on my engine which otherwise is very much stock and not much messed with

This probably does not help much but if you like I could shot some more picts on the other vacuum hoses later (EGR etc), I’m at work right now …

Thanks
Per

[scivies]

The picture does help Per. If you get a chance later, please let me know where those three lines go. Yours looks like it is all brass and the top portion of mine is made of plastic. I believe that is the only difference. Thanks for the help.

[Robroy]

The left one going out from that triple connection on the pict goes to the carburetor, middle one to the distributor and the third to that black plastic can in the corner of the engine bay (drivers side), I haven’t yet figured out what that is…:confused4:

[scivies]

Per,

I believe the canister you are referring to is the charcoal canister, which is part of the emission system. I believe one line goes to the gas tank and the fumes come from the tank and go through the canister before being vacuumed into the carburator. I do not know how much this would actually effect the running of the Centurion, but I had a Chevrolet Celebrity once that ran terrible until I traced the problem to this canister. After bypassing the canister it ran much better. Thanks for the much needed info!

Scott

[Robroy]

Thanks for the info Scott! I figured that canister had to do with the emission system somehow, just didn’t know how this system worked. Maybe it’s a good idea to bypass it and connect the distributor direct to the carb …..
I’m looking for a place to put the sender unit for a temp gauge and removing that temp controlled vacuum switch would provide such a place and I wouldn’t have to do any T-connection ….on the other hand its nice to keep the stock look on the engine….hm..need to do some thinking about this :confused2:

Let me know if you need some more help/picts regarding the other vacuum lines Scott..:user: