Originally Posted by Cab_Burge
I've seen many motors with Holley carbs that were idling on the transition circuit( the small rectangular slot that should be above primary throttle blades at idle RPM scope) which will open the power valves if the idle vacuum is below the power valve opening vacuum rating which makes the idle mixture very rich scope twocents


I believe the books I've read said the lower portion of the slot (.020 or so) can be exposed without ill effect ? confused

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