This may be it. I can't remember the name, so maybe it is the kill bleeds ??? I'm running those Promax outer plates too.

Ok, image this.... If you have a fuel bowl off of an outer carb and your looking at the facotry metering plate, there are two small holes at the top which are often drilled out in old school tuning. Anyway... the Promax plates have tiny, tiny,, tiny little hex screw "jets" that screw up into their plates. Nobody every talks about those. Anyway, the ones that come with the Promax plates are WAY bigger than stock (bigger holes in them). If you look on the Promax website, they only make vague reference to these "jets" . I researched this a ton to find out what the factory hole size was in stock metering plates. I called Promax and told them I wanted to match that factory stock hole size in my Promax plates..... and they had them. Not listed anywhere, but they had replacements in exactly the right size for cheap. Maybe those are kill bleeds and related to your problem?????

IGNORE ABOVE AND LOOK BELOW - KILL BLEEDS ARE BEHIND THE VACCUM POTS AS NOTED BELOW