80 L82 Vette, w/QJET: Well I changed from my dual snorkle to a nice crome air cleaner and not sure on the vacuume hookup to the distributor vac advance.

Old setup had a vac line from the dist vac adv, to the gooseneck temperature switch, then to front of carb - I kept this as is. This line also had a Y connection going to a spark delay device, and then to the air cleaner assy, and then to the rear pass side port of the carb. Question: do I keep this Y connection and hook this up directly to the rear port of the carb using the spark delay device? or delete all? Not sure what this is actually doing?

I think you could just plug the line that used to go to the air cleaner, and leave the rest as it is. I'd have to see a diagram to be for sure, tho.

I suspect Joel is correct.   And without a diagram I recommend the same thing.

Some of the early emission cars (ours) used a thermo vacuum switch to prevent vacuum advance until the engine is partly warmed up.  I suspect that is in part of what you were looking at.

Thanks guys. So the vacuume advance should come from ported or unported? Are all of the connections through the carb considered ported? If not how can I tell the difference?

Sounds like I can just leave the front connection that goes to the temp switch/bottom front of carb and delete the connection that goes from the rear carb to air cleaner to spark delay valve.

The difference between "ported", and "non-ported" vaccuum is this:
Non-ported means there is vac. there all the time.
Ported means, the vac. is there only above a certain throttle opening/rpm. There is no vaccuum above the throttle blades. Ported vac. is created when the throttle blades are moved(open), and the "ports" above the blades are then subject to a vac. signal. (I don't know if I'm 'splaining it to where it makes sense )
On a system that uses a valve, or solenoid in the vac. line to the dist., there should be constant vac. on one side of the valve/sol., and none to the dist. side, until the valve/sol. opens. (Does this make any sense to anyone but me!?) Adams' Apple38656.8369791667

So are you saying, on the carb (Qjet) there are ported and non ported vac signals. If the car is at idle the ported vac lines have little or no vac until you give it some gas, and the non ported have full vac all the time regardless of engine speed??

What should the vac advance be connected to? ported? or non ported?

 

Yes, on the first question, both parts.
The answer to the second question would depend on whether or not it has a solenoid. If the system has a vac. solenoid for the dist., then there would be full(non-ported)sol. input, and the sol. would control the application of vac. to the dist.
If there is no solenoid, then the dist. would have a ported vac. sig.
The "solenoid" could be electrical, or thermal controled.

Yes Joel, not only do you make sense, but you are right on the money.

The non-ported to the air cleaner is usually on the pass side top corner of a Q-jet.  The ported connectors are lower.

kstyer38661.8361805556

OK, I follow your response but:

What should the vac advance be connected to? ported? or non ported? and why?

 

See above response to this question!

"The answer to the second question would depend on whether or not it has a solenoid. If the system has a vac. solenoid for the dist., then there would be full(non-ported)sol. input, and the sol. would control the application of vac. to the dist. If there is no solenoid, then the dist. would have a ported vac. sig. "

On a system with no emissions controls for the dist., the vac. will be ported. It is done this way to keep the dist. from being fully advanced all the time.

On the system with emiss. controls for the dist., the vac. is full time(non-ported) to the solenoid. The vac. to the dist. is controled by the solenoid, as needed.