Thread: Vacuum line???

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I have used both sides of the vacuum ports on a carb for advance pot-seems to have more grunt at full time. What do you guys think?

Could be a # of things Cam, carb base gasket leak, diaphram bad? advance plate not free?? You didn't give much to go on.

I am just asking-you hear of guys using both. I usually use the full time vacuum when I set it up.

Using full manifold vacuum rather than ported is the way to go.

USA is right.

Some Fords from the 50's and maybe earlier use both, but that's due to no mechanical advance in their distributors.

You shouldn't see any HP gained or lost due to selecting either ported or full-time.
Full throttle backs off the vacuum advance timing regardless of vacuum source.

You need full-time - or manifold - vacuum to the advance can at idle and low speeds to avoid overheating.
Low speed mixtures are lean and require more time to burn.