Weird spark at plug

[46yblock]

A friend of mine called me several days ago for help, as he couldnt get his Packard started. The vehicle is a beauty with a motor of less than 3000 miles.
First check was the Edelbrock, and there was gas getting to the primaries. Next we pulled a plug. I grounded it to the valve cover as he cranked, and surprise, there was spark but it was intermittent and jumping from the base of the center electrode, just above the porcelain, to the metal side of the plug.
The plugs were gas fouled, and I really couldnt tell if they had been running rich at that point. He said the car had initially fired and sputtered, and would only keep firing if the starter was engaged. Soon it wouldnt fire at all.
So, weird spark, great engine, we started thinking about the electronic ignition.
I went home and thought about an incident in the recent past on my Ranger. Winter, cold, tried to start it, died, pumped throttle a couple extra times, and it flat would not start for anything, even after waiting a day. Changed the plugs and fine ever since.
So I called him up and suggested putting in a new set of plugs. He did, it started immediately.
Maybe you guys know this but I didnt. Gas fouled plugs build up a coating that can only be blasted off, or burnt off in something like a charcoal fire. Even brand new plugs installed but then flooded and which fire a few times.