Holley stumble trouble

Pin drills are on the way. Gonna yank the carb again tonight and break it down for another inspection and cleaning. Will measure all bleeds and report back with results and some pics of metering block.
I’m beginning to wonder if ordering a Proform main body isn’t the way to go here. Could be money well spent if I have to go down the rabbit hole of drilling or filling these factory holes.
Before you pull the carb off hookup a tach and slowly bring the rpm up to see what rpm the primary boosters start to flow. Don't be surprised if one side starts flowing sooner than the other if you are using a dual plane intake. Also bring the rpm to 2k and see if the motor runs cleanly, this would be the upper side of the idle transition circuit, you are looking for a lean misfire. All this is done in nuetral. When you check the emulsion well holes in the metering block you may find one or more plugged with crap.