Does this Holley have replaceable bleeds? if so try going up a couple of sizes on the HSAB to see if that helps to start the mains slower. Also one guy on another site that had your problem had a bad metering block gasket to the main body that fixed his booster dribble.Yes they are. I cleaned everything out several times and put the carb back on. I ran out of time so I'll start it in the morning. I didnt find anything clogged so I'm not optimistic.