This kill bleed they are talking about is visible on the inside of the venture. Again, it only helps monitor the rate at which they open. The air bleed in the top of the end metering plate from Promax have to do with the fuel mixture. I’ve used his plates in as sold condition with staggered jets of 88 on dr side and 84 on pass side. Now, I doubt this is your problem but I thought I would mention it while we’re talking about air bleeds. In my shop right now. I have about 22 out board carbs in the stages of restoration. I have 4 of my own carbs in this bunch that are later issue 4365s and 2 are customers. I was checking things over before I started assembly of the 2 from my customer when I noticed the idle air bleeds On the outside of the throat were way too small. The main air bleeds looked about right. I guaged them both and they were both .037. They should be .039 main and .051 for the idle. I checked all my other 20 440 carbs of all number( both 69 and 70) and they were all the correct .039 and .051. This was a factory mistake that got out. I’m not sure if that much difference in the smaller idle air bleed could haven adjusted out with the screw but it would surely have been too rich. No I don’t think this is your problem but it certainly brings up the idea that the factory did make mistakes from time to time.