Thread: Just Wondering

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I really don't know the exact difference either, but I think this is correct. On the front of a typical carb like an Edelbrock are two little vacuum ports. One has constant vacuum the entire time the engine is running. The other one only puts out vacuum as the engine accellerates, and is usually used to run a vacuum advance on a distributor. If you hook up the vacuum advance to the constant port it advances the dist too soon.

That may be way off base, and not answer your question, but at least maybe someone who knows will tell us the real answer.

Don