66 dart with a strange ignition issue

I've never seen anything like this but my 66 dart with a 225 has no spark on 3 of the cylinders, when I go to one of the plug wires with no spark and pull the end of the wire out from the distributor just a bit it'll start arcing and that cylinder will start firing.

Stopped by the parts store today and got a set of wires but there is no change. Cap and rotor both look brand new but not bought by me so I'm not sure. What could cause the wire to get spark when unpluged and arcing, but not when its actually pluged in? Where do I even start on this one?

Engine was running fine a few weeks ago when I bought the car but seemed to start running terrible out of nowhere, along my path I decided to check the ignition timing and everything was going good until #1 lost spark. I then checked the other cylinders using my timing light to see if they're firing and #5 and #6 are dead too, but 2, 3, and 4 are look perfectly normal. And also #1 now has intermittent spark (fires a few times and stops for a second and fires a few more times).

Sorry for long story and bad gramar, any helps appreciated. One more thing to add I think I might be hearing some arcing inside of the distributor (makes sense) but it's hard to tell with all the other rattles this car makes.