Most carburetion problems are actually in the ignition.

If the wires from your pickup are not twisted together, try twisting them up.  Twisting the wires together along their full length allows the wires to reject EMI through the principle of common mode rejection where the EMI affects both wires equally and cancels out.

You're too far down the rabbit hole now, but what you should done is a diagnostics before a teardown.  In this case, it would mean pressurizing the cooling system to see if it holds pressure.  Then a compression test to make sure the cylinders are doing good.  Brent has a lot of experience here and right now, you have to go with the intake gaskets as the culprit.  You could also be dealing with a casting issue.  You might be in the position of putting things back together and taking due diligence to make sure the intake isn't leaking (this time), then pressure testing to make sure it holds pressure.

You can't run anything from the coil + other than the coil.  If you want to have the pump turn on only when the engine is running, use a relay with the trigger coming from the alternator stator terminal.

Oddly enough, there's a company called Ohio Crankshaft (https://ohiocrank.com/) that is one of the best known crank shops.  Not too far from you.

The parts are really core to the maintenance of the FE in the sport.  I wouldn't rule out farming out the casting to an overseas enterprise and doing the machine work in your shop.

Any metal hole grows with heat, alum or iron, as do the cranks.  I can't hear the video where I am watching it, will watch later, but I would not equate a bore size change alone into oil clearance

Plus, the metal grows in all directions, not just out away from the bore.