Brake Booster - vacuum

[Cyrix2k]

How much vacuum should the brake booster pull? I'm busy tracing down what could cause a rough idle on my m50 swap and it ran a lot smoother when I pulled the brake booster vacuum line off the manifold & plugged it temporarily. How would I verify proper operation of the booster? I don't hear hissing.

Thanks!

[FLG]

Hook up a vac tester to the booster and see if it holds. If it doesn't either the hose going to it is ripped somewhere or the diaphragm in the booster is bad.

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