I have an amc 360 with a HEI dizzy in my project jeep and the time to start it up has come. I cranked it over the other day to see if things turned freely. I didn't have plug wires on it and I noticed the distributor arcing between the plugs on top of it. Then when I put plugs and wires on there is no spark but I have power going into the dizzy. So I thought that I blew something in the distributor so I started replacing things one by one. I have changed out everything in it and still no spark. First I changed the control module, then coil, then pickup, then capacitor. and still nothing. So what the heck is going wrong. I have all but gouged my eyes out over this thing.
It probably wasn't arcing between spark plug terminals,
What you probably saw was high voltage leaking from under the coil cover to the terminals or to the distributor base to reach 'Ground'...
What you probably have wrong is the center button under the coil has come apart, and/or the insulation disk (rubber/silicone) has given up and is letting the spark energy leak out every which way.
VERY COMMON with GM HEI's, and the only way you can fix that issue is with a good quality center button and insulator disk.
At this point, Your rotor is blown through, and you will probably find 'Red Dust' under the rotor and on top the advance weights.
If you look closely, you will probably see the weights/pins have been eaten away somewhat (That's were the 'Red Dust' is coming from).
When the high voltage blows through the rotor, the weights and distributor shaft are the closest 'Ground' for the high voltage.
When the high voltage strikes the weights, it will weld them to the pins they pivot on,
And then the weights break that weld, releasing 'Red Dust'.
Since the only way to make 'Red Dust' is by burning all the carbon out of steel (It's IRON rust, not steel rust) the high voltage discharges are the only thing hot enough to do that, and that tells you right away that you have rotor blow-through.
I suggest you get a new, HIGH QUALITY Distributor cap, in some color other than black,
And make sure it has BRASS TERMINALS!
(Not brass washed aluminum, take a pocket knife and scratch one, make sure it's brass all the way through!)
Also make sure you use a HIGH QUALITY ROTOR,
HIGH QUALITY CENTER BUTTON,
AND HIGH QUALITY INSULATOR DISK.
The only place I know of to get all that in one place is an MSD distributor cap kit.
Switch your coil over to the MSD cap, install the rotor and see if that helps your situation.
You might also make sure your distributor is getting a good ground to the housing.
Most people assume the housing mounted in the engine is enough, but often times.... It's not.
Oil reside builds up around the distributor housing and breaks contact with raw metal,
And the housing corrodes over, oxidized aluminum IS NOT a conductor, so pretty soon your distributor hosing is in INSUFFICIENT conductor for your ignition to work correctly.
If you purchased the 'Cheap' HEI's off the internet,
Then you might want to make sure you distributor/camshaft gears are still intact.
Doesn't take long for those cheap distributor gears to run the camshaft gear and not turn the distributor shaft at all, or at least far enough out of time you can't get the engine running...