I find it amusing that people will spend vast amounts of time on Holley carbs "drilling this circuit" or "swapping out this air bleed" or "trying this modification" but won't spend some time learning how AFB's work which are the simplest of devices.
BAM...
I've never drilled this or swaped air bleeds, as a matter of fact Most of the holleys I've run haven't even had air bleeds. I've swaped out Eddy 750's twice for 750 DP's, and a carter 625 comp series for a 750 and evey time the car dropped et w/ no other mods. Mild 440 w/ brand new Eddy 750 (tuned) went from 13.11 (at best) to 12.90 w/ a 20+y/o holley and a rebuild kit. 383 went from 12.89 to 12.68 with a 750DP tuned for a 360, and a 340 went from 14.20 to 13.82 w/ a 750HP. Go to any car show and look under the hood and you'l find lots of Eddy/Carters, go to the track and look under the hood and you'll see lots of Holleys. Just how it is.
