It's hard to diagnose via the internet as we can't see or hear the operation of your set up, along with just the supplied info on hand, that being said I like to start with the basics to sometimes cover the most obvious often overlooked, you gave no mention of checking/setting fuel level in each bowl, to me this is the first operational/running step after confirming all mechanical installation procedures...


I'll mention this just for sh!ts and giggles: but I've come across 2 guys so far over the years that either daunted or unfamiliar with the set up, that have installed the center carb as delivered new from Holley, unfortunately Holley attaches and clips a hose from the PCV port to the bowl vent tube (why?), yeah the set up runs! (barely), but the PCV "vacuums" the bowl dry of fuel... it's simple problems like this that can cause some to render " complex solutions to simple problems", you/we need to know that all of the basics from installation to operational set up have been performed

Mike