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What is the ideal vacuum reading for an engine at max rpm for max power? Mine shows less than 2 but more than 0 on a cheap gauge, with a 4150 carb. Thinking about going to a 4500 carb.


Bud Lowe, Seattle, WA


 If I'm reading your question right you are talking about manifold vacuum and not crankcase vacuum with an external pump? If so, "0" is best. As close as you can get to that is best. Any vacuum indicates a restriction in the Intake tract. Could be the carb, manifold, runners, etc. 2 in. is'nt that bad really.

Hope this helps.