Holley/Demon Carb stumble

I don't know if this valid to extrapolate from, but most of my headaches started after TurboAction tightened up the converter in my Barracuda (at my request).
Yes I messed with the carb (actually a several) but a big help was knocking some timing off (slowing the secondary advance) which starting a little lower in the rpm.

Its possible the the engine is seeing higher load (at those rpms), is spinning up just that much slower, and effecting the burn - or just making it less tolerant of too much lead (which the loose converter covered up like slipping the clutch so we don't stall an engine that isn't yet spinning at an rpm for load).