Arcing across coil terminals

Update/clarification. I physically observed the arcing between the positive and negative coil terminals and the primary wire. I did not observe any arcing from the coil to the distributor, however based on the carbon tracks on the wire it seems likely that was happening as well. The coil was that close to the distributor because the negative lead would not reach. I extended the wire and moved the coil back. Also double checked point gap, its at 0.014". Coil showed .6 ohms between terminals, and 9.5k from center to positive. Within specs for the UC-12x. I checked the tower very closely for cracks or carbon tracks. Very faint carbon deposits, but no cracks.

2 of my plugs were badly fouled, so I replaced them. Car runs fine now, don't see any arcing. I won't be sure everything is good until I have another 100+ degree day and the car has run and then sat for a while in the sun (highest under-hood temps). This is when problems always pop up.