HEI Conversion Question and Holley 2280 Lingering Issue

1983 W-150 318 2-V. Mostly stock with a Melling MTD-1 cam and the aforementioned HEI conversion. OE emissions equipment is installed and (mostly) working. The thermostatic ported vacuum switches to the EGR and vac advance are effectively "failed open" but my issues are cold & hot, so not thinking those are part of the problem. Rebuilt Holley 2280 made from three different Holley 2280s until I got enough parts that were good enough to feel comfortable with the carb. Rebushed the throttle shaft on the installed carb.

Starts and idles great (most of the time; more on that.)

Coil and module are mounted on the driver fender well. Recently, I pulled the factory harness and rebuilt it using Weather-Pack and Metri-Pack connectors and made an underhood fuse/relay box to tighten up the wiring as well as to fix a few things that had been going on with the truck since I purchased it, specifically extremely high voltage from the alternator. This was fixed by adding an "ignition" relay for the voltage regulator. This relay also powers the coil. It is triggered by the original "Hot in Run & Start" circuit fed from the bulkhead connector at position 2 via J10-14RD wire.

First, the persistent issue I've had with the carb. Occasionally and usually without warning or anything I can determine to be a trigger, the needle will hang open after the vehicle has been heated up and the engine will not start due to flooding. The only remedy is to take the air filter housing off, tap on the fuel bowl, and then it will be fine. This doesn't happen after an immediate restart, but it also doesn't require the engine to completely cool down either. It is seemingly random. I have also had three different carb bodies on the engine, several needle and seat sets, and a few floats. No combination seems to be immune to this. I can't believe that this level of a flaw was just acceptable in a production carb. Sometimes I go for months without an occurrence, sometimes twice in a week.

Second issue is a random stumble/misfire. I can't tell if it is completely tied up with the rewire or if it is a slowly worsening issue. The HEI conversion has been on the truck for well over two years, I just never really cleaned up the wires until a few months ago. During this rewire I also realized the distributor was bad and it was replaced as well (reluctor was banging into the pickup; clip on the advance mechanism broke and the pickup was tilted in, surprised I saw no noticeable misfiring, or at least no more than what I had considered "normal"). That said, since I've been driving the truck since the rewire, I've noticed more and more stumbles and now sort of a random but consistent with RPM misfire. After some hunting around, I noticed that the pick-up wires are supposed to be a twisted pair. This is not the case with my set up. Would this alone be enough to cause a random and worsening misfire trend? Anything else I should look at in the interim?