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Pete. (l33t FS)
Pete. (l33t FS) MegaDork
3/25/23 4:34 p.m.

One thing to note is that Holley terminology can be misleading.  The "idle" circuit is more of a low speed circuit that boost fueling before the booster gets fuel moving.  The idle mixture screw merely releases air and fuel emulsion from that circuit to below the throttle plates.

A lot of tip in stumbles are really just a lean idle circuit.  People bandage over it with big accelerator pump cams and squirters, but the real fix is in redrilling the idle jets, which are a fixed part of the metering block in Holleys.  Better aftermarket carbs have replaceable jets for the idle feed restrictions, but if you don't want to buy a set of aftermarket metering blocks, ONCE YOU HAVE THE IGNITION WORKING OKAY you can get a pin vise and small drill set and carefully open those up.

What you will probably find is that tip-in and low speed drivability get much improved, and the idle mixture screws get more responsive instead of needing to be 3 turns out...

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