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The question in my mind is what role, if any, does slide spring rate play with respect to CV carb air/fuel mixtures, presuming at least adequate spring pressure, whatever "adequate" is for a given carb setup?



As long as carb operation is well into the main circuit, the spring should have no substantial effect on mixture. Opening more quickly than the manufacturer intended is no different than pulling the slide/needle up manually on a pair of non-CV carbs. The difference is at low RPM, where the spring limits the throttle to opening at a rate supported by the pilot and transition circuits. The spring allows the idle circuit to be designed leaner, and mains to come in later. The potential drawbacks to lightening the spring are disturbing the metering relationship at low RPM (which can create the low-speed bog) and the possibility of mid-throttle surging.

'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy