[s15laynrubba]

I will probably get beaned in the head for this question. I am running a Edelbrock 1405.Which fittings on the carb is manifold and which is ported. Or are the fittings on the carb ported? Is manifold vacuum actually the vacuum fittings located on the manifold? This has confused me more than anything.I know its probably simple, thus me getting beaned in the head ....Jay

[DoubleVision]

the fitting that pulls vacuum off idle is ported, the other is manifold.

[drlindz]

Not sure about Edelbrock but on Holleys the ported vacuum ports are above the throttle plates and the manifold ports are below the throttle plates. Any ports on your manifold are manifold vacuum ports.The manifold ports on carbs are usally located at the base of the carb.

[Steve B]

You can tell them apart with the following test: With the engine running, the manifold port will have vacuum at idle. The ported one will not have any vacuum at idle, but you can feel it start in as you open the throttle.

[Frisco]

Edelbrock carbs have three vacuum ports on the front base of the carb. The small one on the passenger side is 'ported' vacuum. The large one in the middle is for the PCV hose. The small one on the drivers side is for 'full' vacuum.

There is also a large port (usually plugged) on the rear of the carb base. This would be used for power brake booster.

Another source for 'full' vacuum would be to put a fitting in the pipe tapped hole (also usually plugged) that is in the intake manifold plenum just behind the carb mounting flange.

[s15laynrubba]

Thank you very much, I finally understand it....Jay