Here's the deal though, man....
You already said you put 12v directly to the coil and it wouldn't run. If that's the case, then it's ok to be obsessing about the voltage drops and such if you wish, but in my experience these cars will lose voltage through the wiring. My Valiant does it...my Dart does it.
that was with us assuming that the battery was staying at 12volts while cranking, but it infact wasnt.
The stock coil will work at about 6V. It SHOULD have whatever full voltage is available when starting but I'm confident at 8-10V the ignition system will function.
Here's my suggestions to hopefully move this forward and get a resolution, and I don't mean this rudely:
1. Stop obsessing about the EGR timer, speed sensor etc. That stuff is just there. It has zilch to do with your problem.
those pics were posted because someone had asked doe them to see where the other blue wires went.
2. Please perform the test that people are recommending. Hook the battery up, get a helper to turn the key while you pull off a plug wire and hold it next to the block where there's a good ground. It's either going to spark/zap you or you get nothing.
in progress
In relation to that, it's not as scientific as you are making it out to be. It's either A. you get something, B. you get nothing. You don;t have to do the "how wide should a spark be, what color, what duration, what angle etc.". Just.check.for.a.spark.holding.the.end.of.the.plug.or.wire.with.a.screwdriver.stuck.into.it.next.to.the.block.
I said through the distributor and cap as well. The coil test is fine too but AT THE SPARKPLUG.
The reason for this is it would be mighty embarrassing to go through all this to find out yes you DO have spark at the plugs and it was a fuel problem all this time. I've had quite a few issues with this holley and rebuilt it with a new brass float seeing as i was having issues with the old one getting stuck. Yes the car ran perfectly fine after the carb was rebuilt. That being said once im done with the spark plug wire test i will moat likely be pull the top up a little to see if it is stuck again. But I have the see through fuel filter which is completely full and if i move the valve I can see fuel squirt inside like its supposed to. I separated the fuel line from the carb and when I spin the motor over fuel is coming out of the feed line to the carb as well.
3. Any test you do requires the key to be turned to START inside the car by hand. The jumping the relay just spins the engine and if I said to do that earlier then I should have known better. this i caught myself and realised the proper voltage wouldnt be applied.
4. Have you had the distributor cap off to see if the rotor is broken? If it spins when the engine spins? It is IMPORTANT THAT YOU UNDERSTAND WHY YOU MUST VERIFY THESE THINGS before you OCD about wiring. Ive had the cap off and inspected it and the rotor. The rotor spins with the motor. Ive even removed The distributor to inspect it, reset the motor at TDC and reinstalled the distributor with the rotor just under the number 1cylinder tower like it says in the book.
Please post back your results of THESE tests. Meaning the answer to yes or no you have spark at the plug. Yes or not the rotor button is ok and not scorched to death. Yes or no the rotor button turns when the engine spins.