Thread: How do you measure vacuum?

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I always use a vacuum guage just as you did. I suppose there are other ways but thats how I learned.

You'll be fine with doing it as you did. Putting it in gear, setting the e-brake, hopping out to blip the throttle is a fine way to see your vehicle go winging through the back of the garage - maybe with you hanging on to the throttle linkage for dear life.

Usually, smooth idle, 15-21 inches of vacuum with a stock to mild cam, and none to very little needle movement at idle is what you are looking for. An ~4" gauge is best, but a small, 2-1/16" will usually get you close enough